From 5506de97cffbb5484c0770814c1c7243edb8fbff Mon Sep 17 00:00:00 2001
From: PPsyrius <19505219+PPsyrius@users.noreply.github.com>
Date: Thu, 1 Feb 2024 07:19:48 +0700
Subject: [PATCH] Add United Kingdom's Whit Monday holidays for pre-1971 years
 (#1668)

Co-authored-by: ~Jhellico <KJhellico@users.noreply.github.com>
---
 holidays/countries/isle_of_man.py      |  4 +++
 holidays/countries/united_kingdom.py   | 28 +++++++++++++++
 snapshots/countries/GB_ENG.json        | 21 ++++++++++++
 snapshots/countries/GB_NIR.json        | 21 ++++++++++++
 snapshots/countries/GB_WLS.json        | 21 ++++++++++++
 snapshots/countries/IM_COMMON.json     | 21 ++++++++++++
 snapshots/countries/UK_ENG.json        | 21 ++++++++++++
 snapshots/countries/UK_NIR.json        | 21 ++++++++++++
 snapshots/countries/UK_WLS.json        | 21 ++++++++++++
 tests/countries/test_isle_of_man.py    |  1 +
 tests/countries/test_united_kingdom.py | 47 ++++++++++++++++++++++++++
 11 files changed, 227 insertions(+)

diff --git a/holidays/countries/isle_of_man.py b/holidays/countries/isle_of_man.py
index 6e403ecba..9779d4ff6 100644
--- a/holidays/countries/isle_of_man.py
+++ b/holidays/countries/isle_of_man.py
@@ -35,6 +35,10 @@ def _populate_public_holidays(self) -> None:
         # Easter Monday
         self._add_easter_monday("Easter Monday")
 
+        # Whit Monday.
+        if self._year <= 1970:
+            self._add_whit_monday("Whit Monday")
+
         # Late Summer bank holiday (last Monday in August)
         if self._year >= 1971:
             self._add_holiday_last_mon_of_aug("Late Summer Bank Holiday")
diff --git a/holidays/countries/united_kingdom.py b/holidays/countries/united_kingdom.py
index f158607ba..62d70cc5d 100644
--- a/holidays/countries/united_kingdom.py
+++ b/holidays/countries/united_kingdom.py
@@ -25,8 +25,14 @@ class UnitedKingdom(ObservedHolidayBase, ChristianHolidays, InternationalHoliday
     """
     References:
     - https://en.wikipedia.org/wiki/Public_holidays_in_the_United_Kingdom
+    - https://archive.org/details/treatiseonbanki00walk/page/334/mode/2up
     - https://www.gov.uk/bank-holidays
     - https://www.timeanddate.com/holidays/uk/
+
+    The Anniversary of the Battle of the Boyne bank holiday is proclaimed annually by the
+    Secretary of State for Northern Ireland.
+
+    In-Lieu observance was first provided in the Bank Holidays Extension Act 1875.
     """
 
     country = "GB"
@@ -51,9 +57,15 @@ def __init__(self, *args, **kwargs):
         InternationalHolidays.__init__(self)
         StaticHolidays.__init__(self, UnitedKingdomStaticHolidays)
         kwargs.setdefault("observed_rule", SAT_SUN_TO_NEXT_MON)
+        # Bank Holidays Extension Act 1875
+        kwargs.setdefault("observed_since", 1875)
         super().__init__(*args, **kwargs)
 
     def _populate_public_holidays(self) -> None:
+        # Bank Holidays Act 1871
+        if self._year <= 1871:
+            return None
+
         # Good Friday
         self._add_good_friday("Good Friday")
 
@@ -88,6 +100,10 @@ def _populate_public_holidays(self) -> None:
             self._populate_subdiv_wls_public_holidays()
 
     def _populate_subdiv_holidays(self):
+        # Bank Holidays Act 1871
+        if self._year <= 1871:
+            return None
+
         if self.subdiv not in {"SCT", "Scotland"}:
             # New Year's Day
             if self._year >= 1975:
@@ -109,6 +125,10 @@ def _populate_subdiv_eng_public_holidays(self):
         # Easter Monday
         self._add_easter_monday("Easter Monday")
 
+        # Whit Monday.
+        if self._year <= 1970:
+            self._add_whit_monday("Whit Monday")
+
         # Late Summer bank holiday (last Monday in August)
         if self._year >= 1971:
             self._add_holiday_last_mon_of_aug("Late Summer Bank Holiday")
@@ -121,6 +141,10 @@ def _populate_subdiv_nir_public_holidays(self):
         # Easter Monday
         self._add_easter_monday("Easter Monday")
 
+        # Whit Monday.
+        if self._year <= 1970:
+            self._add_whit_monday("Whit Monday")
+
         # Battle of the Boyne
         self._add_observed(self._add_holiday_jul_12("Battle of the Boyne"))
 
@@ -161,6 +185,10 @@ def _populate_subdiv_wls_public_holidays(self):
         # Easter Monday
         self._add_easter_monday("Easter Monday")
 
+        # Whit Monday.
+        if self._year <= 1970:
+            self._add_whit_monday("Whit Monday")
+
         # Late Summer bank holiday (last Monday in August)
         if self._year >= 1971:
             self._add_holiday_last_mon_of_aug("Late Summer Bank Holiday")
diff --git a/snapshots/countries/GB_ENG.json b/snapshots/countries/GB_ENG.json
index 3198045fb..fb8aec32f 100644
--- a/snapshots/countries/GB_ENG.json
+++ b/snapshots/countries/GB_ENG.json
@@ -1,96 +1,117 @@
 {
     "1950-04-07": "Good Friday",
     "1950-04-10": "Easter Monday",
+    "1950-05-29": "Whit Monday",
     "1950-12-25": "Christmas Day",
     "1950-12-26": "Boxing Day",
     "1951-03-23": "Good Friday",
     "1951-03-26": "Easter Monday",
+    "1951-05-14": "Whit Monday",
     "1951-12-25": "Christmas Day",
     "1951-12-26": "Boxing Day",
     "1952-04-11": "Good Friday",
     "1952-04-14": "Easter Monday",
+    "1952-06-02": "Whit Monday",
     "1952-12-25": "Christmas Day",
     "1952-12-26": "Boxing Day",
     "1953-04-03": "Good Friday",
     "1953-04-06": "Easter Monday",
+    "1953-05-25": "Whit Monday",
     "1953-12-25": "Christmas Day",
     "1953-12-26": "Boxing Day",
     "1953-12-28": "Boxing Day (observed)",
     "1954-04-16": "Good Friday",
     "1954-04-19": "Easter Monday",
+    "1954-06-07": "Whit Monday",
     "1954-12-25": "Christmas Day",
     "1954-12-26": "Boxing Day",
     "1954-12-27": "Christmas Day (observed)",
     "1954-12-28": "Boxing Day (observed)",
     "1955-04-08": "Good Friday",
     "1955-04-11": "Easter Monday",
+    "1955-05-30": "Whit Monday",
     "1955-12-25": "Christmas Day",
     "1955-12-26": "Boxing Day",
     "1955-12-27": "Christmas Day (observed)",
     "1956-03-30": "Good Friday",
     "1956-04-02": "Easter Monday",
+    "1956-05-21": "Whit Monday",
     "1956-12-25": "Christmas Day",
     "1956-12-26": "Boxing Day",
     "1957-04-19": "Good Friday",
     "1957-04-22": "Easter Monday",
+    "1957-06-10": "Whit Monday",
     "1957-12-25": "Christmas Day",
     "1957-12-26": "Boxing Day",
     "1958-04-04": "Good Friday",
     "1958-04-07": "Easter Monday",
+    "1958-05-26": "Whit Monday",
     "1958-12-25": "Christmas Day",
     "1958-12-26": "Boxing Day",
     "1959-03-27": "Good Friday",
     "1959-03-30": "Easter Monday",
+    "1959-05-18": "Whit Monday",
     "1959-12-25": "Christmas Day",
     "1959-12-26": "Boxing Day",
     "1959-12-28": "Boxing Day (observed)",
     "1960-04-15": "Good Friday",
     "1960-04-18": "Easter Monday",
+    "1960-06-06": "Whit Monday",
     "1960-12-25": "Christmas Day",
     "1960-12-26": "Boxing Day",
     "1960-12-27": "Christmas Day (observed)",
     "1961-03-31": "Good Friday",
     "1961-04-03": "Easter Monday",
+    "1961-05-22": "Whit Monday",
     "1961-12-25": "Christmas Day",
     "1961-12-26": "Boxing Day",
     "1962-04-20": "Good Friday",
     "1962-04-23": "Easter Monday",
+    "1962-06-11": "Whit Monday",
     "1962-12-25": "Christmas Day",
     "1962-12-26": "Boxing Day",
     "1963-04-12": "Good Friday",
     "1963-04-15": "Easter Monday",
+    "1963-06-03": "Whit Monday",
     "1963-12-25": "Christmas Day",
     "1963-12-26": "Boxing Day",
     "1964-03-27": "Good Friday",
     "1964-03-30": "Easter Monday",
+    "1964-05-18": "Whit Monday",
     "1964-12-25": "Christmas Day",
     "1964-12-26": "Boxing Day",
     "1964-12-28": "Boxing Day (observed)",
     "1965-04-16": "Good Friday",
     "1965-04-19": "Easter Monday",
+    "1965-06-07": "Whit Monday",
     "1965-12-25": "Christmas Day",
     "1965-12-26": "Boxing Day",
     "1965-12-27": "Christmas Day (observed)",
     "1965-12-28": "Boxing Day (observed)",
     "1966-04-08": "Good Friday",
     "1966-04-11": "Easter Monday",
+    "1966-05-30": "Whit Monday",
     "1966-12-25": "Christmas Day",
     "1966-12-26": "Boxing Day",
     "1966-12-27": "Christmas Day (observed)",
     "1967-03-24": "Good Friday",
     "1967-03-27": "Easter Monday",
+    "1967-05-15": "Whit Monday",
     "1967-12-25": "Christmas Day",
     "1967-12-26": "Boxing Day",
     "1968-04-12": "Good Friday",
     "1968-04-15": "Easter Monday",
+    "1968-06-03": "Whit Monday",
     "1968-12-25": "Christmas Day",
     "1968-12-26": "Boxing Day",
     "1969-04-04": "Good Friday",
     "1969-04-07": "Easter Monday",
+    "1969-05-26": "Whit Monday",
     "1969-12-25": "Christmas Day",
     "1969-12-26": "Boxing Day",
     "1970-03-27": "Good Friday",
     "1970-03-30": "Easter Monday",
+    "1970-05-18": "Whit Monday",
     "1970-12-25": "Christmas Day",
     "1970-12-26": "Boxing Day",
     "1970-12-28": "Boxing Day (observed)",
diff --git a/snapshots/countries/GB_NIR.json b/snapshots/countries/GB_NIR.json
index 6ab174bed..3cfc2e27b 100644
--- a/snapshots/countries/GB_NIR.json
+++ b/snapshots/countries/GB_NIR.json
@@ -2,6 +2,7 @@
     "1950-03-17": "St. Patrick's Day",
     "1950-04-07": "Good Friday",
     "1950-04-10": "Easter Monday",
+    "1950-05-29": "Whit Monday",
     "1950-07-12": "Battle of the Boyne",
     "1950-12-25": "Christmas Day",
     "1950-12-26": "Boxing Day",
@@ -9,12 +10,14 @@
     "1951-03-19": "St. Patrick's Day (observed)",
     "1951-03-23": "Good Friday",
     "1951-03-26": "Easter Monday",
+    "1951-05-14": "Whit Monday",
     "1951-07-12": "Battle of the Boyne",
     "1951-12-25": "Christmas Day",
     "1951-12-26": "Boxing Day",
     "1952-03-17": "St. Patrick's Day",
     "1952-04-11": "Good Friday",
     "1952-04-14": "Easter Monday",
+    "1952-06-02": "Whit Monday",
     "1952-07-12": "Battle of the Boyne",
     "1952-07-14": "Battle of the Boyne (observed)",
     "1952-12-25": "Christmas Day",
@@ -22,6 +25,7 @@
     "1953-03-17": "St. Patrick's Day",
     "1953-04-03": "Good Friday",
     "1953-04-06": "Easter Monday",
+    "1953-05-25": "Whit Monday",
     "1953-07-12": "Battle of the Boyne",
     "1953-07-13": "Battle of the Boyne (observed)",
     "1953-12-25": "Christmas Day",
@@ -30,6 +34,7 @@
     "1954-03-17": "St. Patrick's Day",
     "1954-04-16": "Good Friday",
     "1954-04-19": "Easter Monday",
+    "1954-06-07": "Whit Monday",
     "1954-07-12": "Battle of the Boyne",
     "1954-12-25": "Christmas Day",
     "1954-12-26": "Boxing Day",
@@ -38,6 +43,7 @@
     "1955-03-17": "St. Patrick's Day",
     "1955-04-08": "Good Friday",
     "1955-04-11": "Easter Monday",
+    "1955-05-30": "Whit Monday",
     "1955-07-12": "Battle of the Boyne",
     "1955-12-25": "Christmas Day",
     "1955-12-26": "Boxing Day",
@@ -46,6 +52,7 @@
     "1956-03-19": "St. Patrick's Day (observed)",
     "1956-03-30": "Good Friday",
     "1956-04-02": "Easter Monday",
+    "1956-05-21": "Whit Monday",
     "1956-07-12": "Battle of the Boyne",
     "1956-12-25": "Christmas Day",
     "1956-12-26": "Boxing Day",
@@ -53,12 +60,14 @@
     "1957-03-18": "St. Patrick's Day (observed)",
     "1957-04-19": "Good Friday",
     "1957-04-22": "Easter Monday",
+    "1957-06-10": "Whit Monday",
     "1957-07-12": "Battle of the Boyne",
     "1957-12-25": "Christmas Day",
     "1957-12-26": "Boxing Day",
     "1958-03-17": "St. Patrick's Day",
     "1958-04-04": "Good Friday",
     "1958-04-07": "Easter Monday",
+    "1958-05-26": "Whit Monday",
     "1958-07-12": "Battle of the Boyne",
     "1958-07-14": "Battle of the Boyne (observed)",
     "1958-12-25": "Christmas Day",
@@ -66,6 +75,7 @@
     "1959-03-17": "St. Patrick's Day",
     "1959-03-27": "Good Friday",
     "1959-03-30": "Easter Monday",
+    "1959-05-18": "Whit Monday",
     "1959-07-12": "Battle of the Boyne",
     "1959-07-13": "Battle of the Boyne (observed)",
     "1959-12-25": "Christmas Day",
@@ -74,6 +84,7 @@
     "1960-03-17": "St. Patrick's Day",
     "1960-04-15": "Good Friday",
     "1960-04-18": "Easter Monday",
+    "1960-06-06": "Whit Monday",
     "1960-07-12": "Battle of the Boyne",
     "1960-12-25": "Christmas Day",
     "1960-12-26": "Boxing Day",
@@ -81,6 +92,7 @@
     "1961-03-17": "St. Patrick's Day",
     "1961-03-31": "Good Friday",
     "1961-04-03": "Easter Monday",
+    "1961-05-22": "Whit Monday",
     "1961-07-12": "Battle of the Boyne",
     "1961-12-25": "Christmas Day",
     "1961-12-26": "Boxing Day",
@@ -88,6 +100,7 @@
     "1962-03-19": "St. Patrick's Day (observed)",
     "1962-04-20": "Good Friday",
     "1962-04-23": "Easter Monday",
+    "1962-06-11": "Whit Monday",
     "1962-07-12": "Battle of the Boyne",
     "1962-12-25": "Christmas Day",
     "1962-12-26": "Boxing Day",
@@ -95,12 +108,14 @@
     "1963-03-18": "St. Patrick's Day (observed)",
     "1963-04-12": "Good Friday",
     "1963-04-15": "Easter Monday",
+    "1963-06-03": "Whit Monday",
     "1963-07-12": "Battle of the Boyne",
     "1963-12-25": "Christmas Day",
     "1963-12-26": "Boxing Day",
     "1964-03-17": "St. Patrick's Day",
     "1964-03-27": "Good Friday",
     "1964-03-30": "Easter Monday",
+    "1964-05-18": "Whit Monday",
     "1964-07-12": "Battle of the Boyne",
     "1964-07-13": "Battle of the Boyne (observed)",
     "1964-12-25": "Christmas Day",
@@ -109,6 +124,7 @@
     "1965-03-17": "St. Patrick's Day",
     "1965-04-16": "Good Friday",
     "1965-04-19": "Easter Monday",
+    "1965-06-07": "Whit Monday",
     "1965-07-12": "Battle of the Boyne",
     "1965-12-25": "Christmas Day",
     "1965-12-26": "Boxing Day",
@@ -117,6 +133,7 @@
     "1966-03-17": "St. Patrick's Day",
     "1966-04-08": "Good Friday",
     "1966-04-11": "Easter Monday",
+    "1966-05-30": "Whit Monday",
     "1966-07-12": "Battle of the Boyne",
     "1966-12-25": "Christmas Day",
     "1966-12-26": "Boxing Day",
@@ -124,6 +141,7 @@
     "1967-03-17": "St. Patrick's Day",
     "1967-03-24": "Good Friday",
     "1967-03-27": "Easter Monday",
+    "1967-05-15": "Whit Monday",
     "1967-07-12": "Battle of the Boyne",
     "1967-12-25": "Christmas Day",
     "1967-12-26": "Boxing Day",
@@ -131,12 +149,14 @@
     "1968-03-18": "St. Patrick's Day (observed)",
     "1968-04-12": "Good Friday",
     "1968-04-15": "Easter Monday",
+    "1968-06-03": "Whit Monday",
     "1968-07-12": "Battle of the Boyne",
     "1968-12-25": "Christmas Day",
     "1968-12-26": "Boxing Day",
     "1969-03-17": "St. Patrick's Day",
     "1969-04-04": "Good Friday",
     "1969-04-07": "Easter Monday",
+    "1969-05-26": "Whit Monday",
     "1969-07-12": "Battle of the Boyne",
     "1969-07-14": "Battle of the Boyne (observed)",
     "1969-12-25": "Christmas Day",
@@ -144,6 +164,7 @@
     "1970-03-17": "St. Patrick's Day",
     "1970-03-27": "Good Friday",
     "1970-03-30": "Easter Monday",
+    "1970-05-18": "Whit Monday",
     "1970-07-12": "Battle of the Boyne",
     "1970-07-13": "Battle of the Boyne (observed)",
     "1970-12-25": "Christmas Day",
diff --git a/snapshots/countries/GB_WLS.json b/snapshots/countries/GB_WLS.json
index 3198045fb..fb8aec32f 100644
--- a/snapshots/countries/GB_WLS.json
+++ b/snapshots/countries/GB_WLS.json
@@ -1,96 +1,117 @@
 {
     "1950-04-07": "Good Friday",
     "1950-04-10": "Easter Monday",
+    "1950-05-29": "Whit Monday",
     "1950-12-25": "Christmas Day",
     "1950-12-26": "Boxing Day",
     "1951-03-23": "Good Friday",
     "1951-03-26": "Easter Monday",
+    "1951-05-14": "Whit Monday",
     "1951-12-25": "Christmas Day",
     "1951-12-26": "Boxing Day",
     "1952-04-11": "Good Friday",
     "1952-04-14": "Easter Monday",
+    "1952-06-02": "Whit Monday",
     "1952-12-25": "Christmas Day",
     "1952-12-26": "Boxing Day",
     "1953-04-03": "Good Friday",
     "1953-04-06": "Easter Monday",
+    "1953-05-25": "Whit Monday",
     "1953-12-25": "Christmas Day",
     "1953-12-26": "Boxing Day",
     "1953-12-28": "Boxing Day (observed)",
     "1954-04-16": "Good Friday",
     "1954-04-19": "Easter Monday",
+    "1954-06-07": "Whit Monday",
     "1954-12-25": "Christmas Day",
     "1954-12-26": "Boxing Day",
     "1954-12-27": "Christmas Day (observed)",
     "1954-12-28": "Boxing Day (observed)",
     "1955-04-08": "Good Friday",
     "1955-04-11": "Easter Monday",
+    "1955-05-30": "Whit Monday",
     "1955-12-25": "Christmas Day",
     "1955-12-26": "Boxing Day",
     "1955-12-27": "Christmas Day (observed)",
     "1956-03-30": "Good Friday",
     "1956-04-02": "Easter Monday",
+    "1956-05-21": "Whit Monday",
     "1956-12-25": "Christmas Day",
     "1956-12-26": "Boxing Day",
     "1957-04-19": "Good Friday",
     "1957-04-22": "Easter Monday",
+    "1957-06-10": "Whit Monday",
     "1957-12-25": "Christmas Day",
     "1957-12-26": "Boxing Day",
     "1958-04-04": "Good Friday",
     "1958-04-07": "Easter Monday",
+    "1958-05-26": "Whit Monday",
     "1958-12-25": "Christmas Day",
     "1958-12-26": "Boxing Day",
     "1959-03-27": "Good Friday",
     "1959-03-30": "Easter Monday",
+    "1959-05-18": "Whit Monday",
     "1959-12-25": "Christmas Day",
     "1959-12-26": "Boxing Day",
     "1959-12-28": "Boxing Day (observed)",
     "1960-04-15": "Good Friday",
     "1960-04-18": "Easter Monday",
+    "1960-06-06": "Whit Monday",
     "1960-12-25": "Christmas Day",
     "1960-12-26": "Boxing Day",
     "1960-12-27": "Christmas Day (observed)",
     "1961-03-31": "Good Friday",
     "1961-04-03": "Easter Monday",
+    "1961-05-22": "Whit Monday",
     "1961-12-25": "Christmas Day",
     "1961-12-26": "Boxing Day",
     "1962-04-20": "Good Friday",
     "1962-04-23": "Easter Monday",
+    "1962-06-11": "Whit Monday",
     "1962-12-25": "Christmas Day",
     "1962-12-26": "Boxing Day",
     "1963-04-12": "Good Friday",
     "1963-04-15": "Easter Monday",
+    "1963-06-03": "Whit Monday",
     "1963-12-25": "Christmas Day",
     "1963-12-26": "Boxing Day",
     "1964-03-27": "Good Friday",
     "1964-03-30": "Easter Monday",
+    "1964-05-18": "Whit Monday",
     "1964-12-25": "Christmas Day",
     "1964-12-26": "Boxing Day",
     "1964-12-28": "Boxing Day (observed)",
     "1965-04-16": "Good Friday",
     "1965-04-19": "Easter Monday",
+    "1965-06-07": "Whit Monday",
     "1965-12-25": "Christmas Day",
     "1965-12-26": "Boxing Day",
     "1965-12-27": "Christmas Day (observed)",
     "1965-12-28": "Boxing Day (observed)",
     "1966-04-08": "Good Friday",
     "1966-04-11": "Easter Monday",
+    "1966-05-30": "Whit Monday",
     "1966-12-25": "Christmas Day",
     "1966-12-26": "Boxing Day",
     "1966-12-27": "Christmas Day (observed)",
     "1967-03-24": "Good Friday",
     "1967-03-27": "Easter Monday",
+    "1967-05-15": "Whit Monday",
     "1967-12-25": "Christmas Day",
     "1967-12-26": "Boxing Day",
     "1968-04-12": "Good Friday",
     "1968-04-15": "Easter Monday",
+    "1968-06-03": "Whit Monday",
     "1968-12-25": "Christmas Day",
     "1968-12-26": "Boxing Day",
     "1969-04-04": "Good Friday",
     "1969-04-07": "Easter Monday",
+    "1969-05-26": "Whit Monday",
     "1969-12-25": "Christmas Day",
     "1969-12-26": "Boxing Day",
     "1970-03-27": "Good Friday",
     "1970-03-30": "Easter Monday",
+    "1970-05-18": "Whit Monday",
     "1970-12-25": "Christmas Day",
     "1970-12-26": "Boxing Day",
     "1970-12-28": "Boxing Day (observed)",
diff --git a/snapshots/countries/IM_COMMON.json b/snapshots/countries/IM_COMMON.json
index 011231682..cf3e2694a 100644
--- a/snapshots/countries/IM_COMMON.json
+++ b/snapshots/countries/IM_COMMON.json
@@ -1,24 +1,28 @@
 {
     "1950-04-07": "Good Friday",
     "1950-04-10": "Easter Monday",
+    "1950-05-29": "Whit Monday",
     "1950-06-02": "TT Bank Holiday",
     "1950-07-05": "Tynwald Day",
     "1950-12-25": "Christmas Day",
     "1950-12-26": "Boxing Day",
     "1951-03-23": "Good Friday",
     "1951-03-26": "Easter Monday",
+    "1951-05-14": "Whit Monday",
     "1951-06-01": "TT Bank Holiday",
     "1951-07-05": "Tynwald Day",
     "1951-12-25": "Christmas Day",
     "1951-12-26": "Boxing Day",
     "1952-04-11": "Good Friday",
     "1952-04-14": "Easter Monday",
+    "1952-06-02": "Whit Monday",
     "1952-06-06": "TT Bank Holiday",
     "1952-07-05": "Tynwald Day",
     "1952-12-25": "Christmas Day",
     "1952-12-26": "Boxing Day",
     "1953-04-03": "Good Friday",
     "1953-04-06": "Easter Monday",
+    "1953-05-25": "Whit Monday",
     "1953-06-05": "TT Bank Holiday",
     "1953-07-05": "Tynwald Day",
     "1953-12-25": "Christmas Day",
@@ -27,6 +31,7 @@
     "1954-04-16": "Good Friday",
     "1954-04-19": "Easter Monday",
     "1954-06-04": "TT Bank Holiday",
+    "1954-06-07": "Whit Monday",
     "1954-07-05": "Tynwald Day",
     "1954-12-25": "Christmas Day",
     "1954-12-26": "Boxing Day",
@@ -34,6 +39,7 @@
     "1954-12-28": "Boxing Day (observed)",
     "1955-04-08": "Good Friday",
     "1955-04-11": "Easter Monday",
+    "1955-05-30": "Whit Monday",
     "1955-06-03": "TT Bank Holiday",
     "1955-07-05": "Tynwald Day",
     "1955-12-25": "Christmas Day",
@@ -41,6 +47,7 @@
     "1955-12-27": "Christmas Day (observed)",
     "1956-03-30": "Good Friday",
     "1956-04-02": "Easter Monday",
+    "1956-05-21": "Whit Monday",
     "1956-06-01": "TT Bank Holiday",
     "1956-07-05": "Tynwald Day",
     "1956-12-25": "Christmas Day",
@@ -48,17 +55,20 @@
     "1957-04-19": "Good Friday",
     "1957-04-22": "Easter Monday",
     "1957-06-07": "TT Bank Holiday",
+    "1957-06-10": "Whit Monday",
     "1957-07-05": "Tynwald Day",
     "1957-12-25": "Christmas Day",
     "1957-12-26": "Boxing Day",
     "1958-04-04": "Good Friday",
     "1958-04-07": "Easter Monday",
+    "1958-05-26": "Whit Monday",
     "1958-06-06": "TT Bank Holiday",
     "1958-07-05": "Tynwald Day",
     "1958-12-25": "Christmas Day",
     "1958-12-26": "Boxing Day",
     "1959-03-27": "Good Friday",
     "1959-03-30": "Easter Monday",
+    "1959-05-18": "Whit Monday",
     "1959-06-05": "TT Bank Holiday",
     "1959-07-05": "Tynwald Day",
     "1959-12-25": "Christmas Day",
@@ -67,12 +77,14 @@
     "1960-04-15": "Good Friday",
     "1960-04-18": "Easter Monday",
     "1960-06-03": "TT Bank Holiday",
+    "1960-06-06": "Whit Monday",
     "1960-07-05": "Tynwald Day",
     "1960-12-25": "Christmas Day",
     "1960-12-26": "Boxing Day",
     "1960-12-27": "Christmas Day (observed)",
     "1961-03-31": "Good Friday",
     "1961-04-03": "Easter Monday",
+    "1961-05-22": "Whit Monday",
     "1961-06-02": "TT Bank Holiday",
     "1961-07-05": "Tynwald Day",
     "1961-12-25": "Christmas Day",
@@ -80,17 +92,20 @@
     "1962-04-20": "Good Friday",
     "1962-04-23": "Easter Monday",
     "1962-06-01": "TT Bank Holiday",
+    "1962-06-11": "Whit Monday",
     "1962-07-05": "Tynwald Day",
     "1962-12-25": "Christmas Day",
     "1962-12-26": "Boxing Day",
     "1963-04-12": "Good Friday",
     "1963-04-15": "Easter Monday",
+    "1963-06-03": "Whit Monday",
     "1963-06-07": "TT Bank Holiday",
     "1963-07-05": "Tynwald Day",
     "1963-12-25": "Christmas Day",
     "1963-12-26": "Boxing Day",
     "1964-03-27": "Good Friday",
     "1964-03-30": "Easter Monday",
+    "1964-05-18": "Whit Monday",
     "1964-06-05": "TT Bank Holiday",
     "1964-07-05": "Tynwald Day",
     "1964-12-25": "Christmas Day",
@@ -99,6 +114,7 @@
     "1965-04-16": "Good Friday",
     "1965-04-19": "Easter Monday",
     "1965-06-04": "TT Bank Holiday",
+    "1965-06-07": "Whit Monday",
     "1965-07-05": "Tynwald Day",
     "1965-12-25": "Christmas Day",
     "1965-12-26": "Boxing Day",
@@ -106,6 +122,7 @@
     "1965-12-28": "Boxing Day (observed)",
     "1966-04-08": "Good Friday",
     "1966-04-11": "Easter Monday",
+    "1966-05-30": "Whit Monday",
     "1966-06-03": "TT Bank Holiday",
     "1966-07-05": "Tynwald Day",
     "1966-12-25": "Christmas Day",
@@ -113,24 +130,28 @@
     "1966-12-27": "Christmas Day (observed)",
     "1967-03-24": "Good Friday",
     "1967-03-27": "Easter Monday",
+    "1967-05-15": "Whit Monday",
     "1967-06-02": "TT Bank Holiday",
     "1967-07-05": "Tynwald Day",
     "1967-12-25": "Christmas Day",
     "1967-12-26": "Boxing Day",
     "1968-04-12": "Good Friday",
     "1968-04-15": "Easter Monday",
+    "1968-06-03": "Whit Monday",
     "1968-06-07": "TT Bank Holiday",
     "1968-07-05": "Tynwald Day",
     "1968-12-25": "Christmas Day",
     "1968-12-26": "Boxing Day",
     "1969-04-04": "Good Friday",
     "1969-04-07": "Easter Monday",
+    "1969-05-26": "Whit Monday",
     "1969-06-06": "TT Bank Holiday",
     "1969-07-05": "Tynwald Day",
     "1969-12-25": "Christmas Day",
     "1969-12-26": "Boxing Day",
     "1970-03-27": "Good Friday",
     "1970-03-30": "Easter Monday",
+    "1970-05-18": "Whit Monday",
     "1970-06-05": "TT Bank Holiday",
     "1970-07-05": "Tynwald Day",
     "1970-12-25": "Christmas Day",
diff --git a/snapshots/countries/UK_ENG.json b/snapshots/countries/UK_ENG.json
index 3198045fb..fb8aec32f 100644
--- a/snapshots/countries/UK_ENG.json
+++ b/snapshots/countries/UK_ENG.json
@@ -1,96 +1,117 @@
 {
     "1950-04-07": "Good Friday",
     "1950-04-10": "Easter Monday",
+    "1950-05-29": "Whit Monday",
     "1950-12-25": "Christmas Day",
     "1950-12-26": "Boxing Day",
     "1951-03-23": "Good Friday",
     "1951-03-26": "Easter Monday",
+    "1951-05-14": "Whit Monday",
     "1951-12-25": "Christmas Day",
     "1951-12-26": "Boxing Day",
     "1952-04-11": "Good Friday",
     "1952-04-14": "Easter Monday",
+    "1952-06-02": "Whit Monday",
     "1952-12-25": "Christmas Day",
     "1952-12-26": "Boxing Day",
     "1953-04-03": "Good Friday",
     "1953-04-06": "Easter Monday",
+    "1953-05-25": "Whit Monday",
     "1953-12-25": "Christmas Day",
     "1953-12-26": "Boxing Day",
     "1953-12-28": "Boxing Day (observed)",
     "1954-04-16": "Good Friday",
     "1954-04-19": "Easter Monday",
+    "1954-06-07": "Whit Monday",
     "1954-12-25": "Christmas Day",
     "1954-12-26": "Boxing Day",
     "1954-12-27": "Christmas Day (observed)",
     "1954-12-28": "Boxing Day (observed)",
     "1955-04-08": "Good Friday",
     "1955-04-11": "Easter Monday",
+    "1955-05-30": "Whit Monday",
     "1955-12-25": "Christmas Day",
     "1955-12-26": "Boxing Day",
     "1955-12-27": "Christmas Day (observed)",
     "1956-03-30": "Good Friday",
     "1956-04-02": "Easter Monday",
+    "1956-05-21": "Whit Monday",
     "1956-12-25": "Christmas Day",
     "1956-12-26": "Boxing Day",
     "1957-04-19": "Good Friday",
     "1957-04-22": "Easter Monday",
+    "1957-06-10": "Whit Monday",
     "1957-12-25": "Christmas Day",
     "1957-12-26": "Boxing Day",
     "1958-04-04": "Good Friday",
     "1958-04-07": "Easter Monday",
+    "1958-05-26": "Whit Monday",
     "1958-12-25": "Christmas Day",
     "1958-12-26": "Boxing Day",
     "1959-03-27": "Good Friday",
     "1959-03-30": "Easter Monday",
+    "1959-05-18": "Whit Monday",
     "1959-12-25": "Christmas Day",
     "1959-12-26": "Boxing Day",
     "1959-12-28": "Boxing Day (observed)",
     "1960-04-15": "Good Friday",
     "1960-04-18": "Easter Monday",
+    "1960-06-06": "Whit Monday",
     "1960-12-25": "Christmas Day",
     "1960-12-26": "Boxing Day",
     "1960-12-27": "Christmas Day (observed)",
     "1961-03-31": "Good Friday",
     "1961-04-03": "Easter Monday",
+    "1961-05-22": "Whit Monday",
     "1961-12-25": "Christmas Day",
     "1961-12-26": "Boxing Day",
     "1962-04-20": "Good Friday",
     "1962-04-23": "Easter Monday",
+    "1962-06-11": "Whit Monday",
     "1962-12-25": "Christmas Day",
     "1962-12-26": "Boxing Day",
     "1963-04-12": "Good Friday",
     "1963-04-15": "Easter Monday",
+    "1963-06-03": "Whit Monday",
     "1963-12-25": "Christmas Day",
     "1963-12-26": "Boxing Day",
     "1964-03-27": "Good Friday",
     "1964-03-30": "Easter Monday",
+    "1964-05-18": "Whit Monday",
     "1964-12-25": "Christmas Day",
     "1964-12-26": "Boxing Day",
     "1964-12-28": "Boxing Day (observed)",
     "1965-04-16": "Good Friday",
     "1965-04-19": "Easter Monday",
+    "1965-06-07": "Whit Monday",
     "1965-12-25": "Christmas Day",
     "1965-12-26": "Boxing Day",
     "1965-12-27": "Christmas Day (observed)",
     "1965-12-28": "Boxing Day (observed)",
     "1966-04-08": "Good Friday",
     "1966-04-11": "Easter Monday",
+    "1966-05-30": "Whit Monday",
     "1966-12-25": "Christmas Day",
     "1966-12-26": "Boxing Day",
     "1966-12-27": "Christmas Day (observed)",
     "1967-03-24": "Good Friday",
     "1967-03-27": "Easter Monday",
+    "1967-05-15": "Whit Monday",
     "1967-12-25": "Christmas Day",
     "1967-12-26": "Boxing Day",
     "1968-04-12": "Good Friday",
     "1968-04-15": "Easter Monday",
+    "1968-06-03": "Whit Monday",
     "1968-12-25": "Christmas Day",
     "1968-12-26": "Boxing Day",
     "1969-04-04": "Good Friday",
     "1969-04-07": "Easter Monday",
+    "1969-05-26": "Whit Monday",
     "1969-12-25": "Christmas Day",
     "1969-12-26": "Boxing Day",
     "1970-03-27": "Good Friday",
     "1970-03-30": "Easter Monday",
+    "1970-05-18": "Whit Monday",
     "1970-12-25": "Christmas Day",
     "1970-12-26": "Boxing Day",
     "1970-12-28": "Boxing Day (observed)",
diff --git a/snapshots/countries/UK_NIR.json b/snapshots/countries/UK_NIR.json
index 6ab174bed..3cfc2e27b 100644
--- a/snapshots/countries/UK_NIR.json
+++ b/snapshots/countries/UK_NIR.json
@@ -2,6 +2,7 @@
     "1950-03-17": "St. Patrick's Day",
     "1950-04-07": "Good Friday",
     "1950-04-10": "Easter Monday",
+    "1950-05-29": "Whit Monday",
     "1950-07-12": "Battle of the Boyne",
     "1950-12-25": "Christmas Day",
     "1950-12-26": "Boxing Day",
@@ -9,12 +10,14 @@
     "1951-03-19": "St. Patrick's Day (observed)",
     "1951-03-23": "Good Friday",
     "1951-03-26": "Easter Monday",
+    "1951-05-14": "Whit Monday",
     "1951-07-12": "Battle of the Boyne",
     "1951-12-25": "Christmas Day",
     "1951-12-26": "Boxing Day",
     "1952-03-17": "St. Patrick's Day",
     "1952-04-11": "Good Friday",
     "1952-04-14": "Easter Monday",
+    "1952-06-02": "Whit Monday",
     "1952-07-12": "Battle of the Boyne",
     "1952-07-14": "Battle of the Boyne (observed)",
     "1952-12-25": "Christmas Day",
@@ -22,6 +25,7 @@
     "1953-03-17": "St. Patrick's Day",
     "1953-04-03": "Good Friday",
     "1953-04-06": "Easter Monday",
+    "1953-05-25": "Whit Monday",
     "1953-07-12": "Battle of the Boyne",
     "1953-07-13": "Battle of the Boyne (observed)",
     "1953-12-25": "Christmas Day",
@@ -30,6 +34,7 @@
     "1954-03-17": "St. Patrick's Day",
     "1954-04-16": "Good Friday",
     "1954-04-19": "Easter Monday",
+    "1954-06-07": "Whit Monday",
     "1954-07-12": "Battle of the Boyne",
     "1954-12-25": "Christmas Day",
     "1954-12-26": "Boxing Day",
@@ -38,6 +43,7 @@
     "1955-03-17": "St. Patrick's Day",
     "1955-04-08": "Good Friday",
     "1955-04-11": "Easter Monday",
+    "1955-05-30": "Whit Monday",
     "1955-07-12": "Battle of the Boyne",
     "1955-12-25": "Christmas Day",
     "1955-12-26": "Boxing Day",
@@ -46,6 +52,7 @@
     "1956-03-19": "St. Patrick's Day (observed)",
     "1956-03-30": "Good Friday",
     "1956-04-02": "Easter Monday",
+    "1956-05-21": "Whit Monday",
     "1956-07-12": "Battle of the Boyne",
     "1956-12-25": "Christmas Day",
     "1956-12-26": "Boxing Day",
@@ -53,12 +60,14 @@
     "1957-03-18": "St. Patrick's Day (observed)",
     "1957-04-19": "Good Friday",
     "1957-04-22": "Easter Monday",
+    "1957-06-10": "Whit Monday",
     "1957-07-12": "Battle of the Boyne",
     "1957-12-25": "Christmas Day",
     "1957-12-26": "Boxing Day",
     "1958-03-17": "St. Patrick's Day",
     "1958-04-04": "Good Friday",
     "1958-04-07": "Easter Monday",
+    "1958-05-26": "Whit Monday",
     "1958-07-12": "Battle of the Boyne",
     "1958-07-14": "Battle of the Boyne (observed)",
     "1958-12-25": "Christmas Day",
@@ -66,6 +75,7 @@
     "1959-03-17": "St. Patrick's Day",
     "1959-03-27": "Good Friday",
     "1959-03-30": "Easter Monday",
+    "1959-05-18": "Whit Monday",
     "1959-07-12": "Battle of the Boyne",
     "1959-07-13": "Battle of the Boyne (observed)",
     "1959-12-25": "Christmas Day",
@@ -74,6 +84,7 @@
     "1960-03-17": "St. Patrick's Day",
     "1960-04-15": "Good Friday",
     "1960-04-18": "Easter Monday",
+    "1960-06-06": "Whit Monday",
     "1960-07-12": "Battle of the Boyne",
     "1960-12-25": "Christmas Day",
     "1960-12-26": "Boxing Day",
@@ -81,6 +92,7 @@
     "1961-03-17": "St. Patrick's Day",
     "1961-03-31": "Good Friday",
     "1961-04-03": "Easter Monday",
+    "1961-05-22": "Whit Monday",
     "1961-07-12": "Battle of the Boyne",
     "1961-12-25": "Christmas Day",
     "1961-12-26": "Boxing Day",
@@ -88,6 +100,7 @@
     "1962-03-19": "St. Patrick's Day (observed)",
     "1962-04-20": "Good Friday",
     "1962-04-23": "Easter Monday",
+    "1962-06-11": "Whit Monday",
     "1962-07-12": "Battle of the Boyne",
     "1962-12-25": "Christmas Day",
     "1962-12-26": "Boxing Day",
@@ -95,12 +108,14 @@
     "1963-03-18": "St. Patrick's Day (observed)",
     "1963-04-12": "Good Friday",
     "1963-04-15": "Easter Monday",
+    "1963-06-03": "Whit Monday",
     "1963-07-12": "Battle of the Boyne",
     "1963-12-25": "Christmas Day",
     "1963-12-26": "Boxing Day",
     "1964-03-17": "St. Patrick's Day",
     "1964-03-27": "Good Friday",
     "1964-03-30": "Easter Monday",
+    "1964-05-18": "Whit Monday",
     "1964-07-12": "Battle of the Boyne",
     "1964-07-13": "Battle of the Boyne (observed)",
     "1964-12-25": "Christmas Day",
@@ -109,6 +124,7 @@
     "1965-03-17": "St. Patrick's Day",
     "1965-04-16": "Good Friday",
     "1965-04-19": "Easter Monday",
+    "1965-06-07": "Whit Monday",
     "1965-07-12": "Battle of the Boyne",
     "1965-12-25": "Christmas Day",
     "1965-12-26": "Boxing Day",
@@ -117,6 +133,7 @@
     "1966-03-17": "St. Patrick's Day",
     "1966-04-08": "Good Friday",
     "1966-04-11": "Easter Monday",
+    "1966-05-30": "Whit Monday",
     "1966-07-12": "Battle of the Boyne",
     "1966-12-25": "Christmas Day",
     "1966-12-26": "Boxing Day",
@@ -124,6 +141,7 @@
     "1967-03-17": "St. Patrick's Day",
     "1967-03-24": "Good Friday",
     "1967-03-27": "Easter Monday",
+    "1967-05-15": "Whit Monday",
     "1967-07-12": "Battle of the Boyne",
     "1967-12-25": "Christmas Day",
     "1967-12-26": "Boxing Day",
@@ -131,12 +149,14 @@
     "1968-03-18": "St. Patrick's Day (observed)",
     "1968-04-12": "Good Friday",
     "1968-04-15": "Easter Monday",
+    "1968-06-03": "Whit Monday",
     "1968-07-12": "Battle of the Boyne",
     "1968-12-25": "Christmas Day",
     "1968-12-26": "Boxing Day",
     "1969-03-17": "St. Patrick's Day",
     "1969-04-04": "Good Friday",
     "1969-04-07": "Easter Monday",
+    "1969-05-26": "Whit Monday",
     "1969-07-12": "Battle of the Boyne",
     "1969-07-14": "Battle of the Boyne (observed)",
     "1969-12-25": "Christmas Day",
@@ -144,6 +164,7 @@
     "1970-03-17": "St. Patrick's Day",
     "1970-03-27": "Good Friday",
     "1970-03-30": "Easter Monday",
+    "1970-05-18": "Whit Monday",
     "1970-07-12": "Battle of the Boyne",
     "1970-07-13": "Battle of the Boyne (observed)",
     "1970-12-25": "Christmas Day",
diff --git a/snapshots/countries/UK_WLS.json b/snapshots/countries/UK_WLS.json
index 3198045fb..fb8aec32f 100644
--- a/snapshots/countries/UK_WLS.json
+++ b/snapshots/countries/UK_WLS.json
@@ -1,96 +1,117 @@
 {
     "1950-04-07": "Good Friday",
     "1950-04-10": "Easter Monday",
+    "1950-05-29": "Whit Monday",
     "1950-12-25": "Christmas Day",
     "1950-12-26": "Boxing Day",
     "1951-03-23": "Good Friday",
     "1951-03-26": "Easter Monday",
+    "1951-05-14": "Whit Monday",
     "1951-12-25": "Christmas Day",
     "1951-12-26": "Boxing Day",
     "1952-04-11": "Good Friday",
     "1952-04-14": "Easter Monday",
+    "1952-06-02": "Whit Monday",
     "1952-12-25": "Christmas Day",
     "1952-12-26": "Boxing Day",
     "1953-04-03": "Good Friday",
     "1953-04-06": "Easter Monday",
+    "1953-05-25": "Whit Monday",
     "1953-12-25": "Christmas Day",
     "1953-12-26": "Boxing Day",
     "1953-12-28": "Boxing Day (observed)",
     "1954-04-16": "Good Friday",
     "1954-04-19": "Easter Monday",
+    "1954-06-07": "Whit Monday",
     "1954-12-25": "Christmas Day",
     "1954-12-26": "Boxing Day",
     "1954-12-27": "Christmas Day (observed)",
     "1954-12-28": "Boxing Day (observed)",
     "1955-04-08": "Good Friday",
     "1955-04-11": "Easter Monday",
+    "1955-05-30": "Whit Monday",
     "1955-12-25": "Christmas Day",
     "1955-12-26": "Boxing Day",
     "1955-12-27": "Christmas Day (observed)",
     "1956-03-30": "Good Friday",
     "1956-04-02": "Easter Monday",
+    "1956-05-21": "Whit Monday",
     "1956-12-25": "Christmas Day",
     "1956-12-26": "Boxing Day",
     "1957-04-19": "Good Friday",
     "1957-04-22": "Easter Monday",
+    "1957-06-10": "Whit Monday",
     "1957-12-25": "Christmas Day",
     "1957-12-26": "Boxing Day",
     "1958-04-04": "Good Friday",
     "1958-04-07": "Easter Monday",
+    "1958-05-26": "Whit Monday",
     "1958-12-25": "Christmas Day",
     "1958-12-26": "Boxing Day",
     "1959-03-27": "Good Friday",
     "1959-03-30": "Easter Monday",
+    "1959-05-18": "Whit Monday",
     "1959-12-25": "Christmas Day",
     "1959-12-26": "Boxing Day",
     "1959-12-28": "Boxing Day (observed)",
     "1960-04-15": "Good Friday",
     "1960-04-18": "Easter Monday",
+    "1960-06-06": "Whit Monday",
     "1960-12-25": "Christmas Day",
     "1960-12-26": "Boxing Day",
     "1960-12-27": "Christmas Day (observed)",
     "1961-03-31": "Good Friday",
     "1961-04-03": "Easter Monday",
+    "1961-05-22": "Whit Monday",
     "1961-12-25": "Christmas Day",
     "1961-12-26": "Boxing Day",
     "1962-04-20": "Good Friday",
     "1962-04-23": "Easter Monday",
+    "1962-06-11": "Whit Monday",
     "1962-12-25": "Christmas Day",
     "1962-12-26": "Boxing Day",
     "1963-04-12": "Good Friday",
     "1963-04-15": "Easter Monday",
+    "1963-06-03": "Whit Monday",
     "1963-12-25": "Christmas Day",
     "1963-12-26": "Boxing Day",
     "1964-03-27": "Good Friday",
     "1964-03-30": "Easter Monday",
+    "1964-05-18": "Whit Monday",
     "1964-12-25": "Christmas Day",
     "1964-12-26": "Boxing Day",
     "1964-12-28": "Boxing Day (observed)",
     "1965-04-16": "Good Friday",
     "1965-04-19": "Easter Monday",
+    "1965-06-07": "Whit Monday",
     "1965-12-25": "Christmas Day",
     "1965-12-26": "Boxing Day",
     "1965-12-27": "Christmas Day (observed)",
     "1965-12-28": "Boxing Day (observed)",
     "1966-04-08": "Good Friday",
     "1966-04-11": "Easter Monday",
+    "1966-05-30": "Whit Monday",
     "1966-12-25": "Christmas Day",
     "1966-12-26": "Boxing Day",
     "1966-12-27": "Christmas Day (observed)",
     "1967-03-24": "Good Friday",
     "1967-03-27": "Easter Monday",
+    "1967-05-15": "Whit Monday",
     "1967-12-25": "Christmas Day",
     "1967-12-26": "Boxing Day",
     "1968-04-12": "Good Friday",
     "1968-04-15": "Easter Monday",
+    "1968-06-03": "Whit Monday",
     "1968-12-25": "Christmas Day",
     "1968-12-26": "Boxing Day",
     "1969-04-04": "Good Friday",
     "1969-04-07": "Easter Monday",
+    "1969-05-26": "Whit Monday",
     "1969-12-25": "Christmas Day",
     "1969-12-26": "Boxing Day",
     "1970-03-27": "Good Friday",
     "1970-03-30": "Easter Monday",
+    "1970-05-18": "Whit Monday",
     "1970-12-25": "Christmas Day",
     "1970-12-26": "Boxing Day",
     "1970-12-28": "Boxing Day (observed)",
diff --git a/tests/countries/test_isle_of_man.py b/tests/countries/test_isle_of_man.py
index 66dd3ce61..cfd493f1d 100644
--- a/tests/countries/test_isle_of_man.py
+++ b/tests/countries/test_isle_of_man.py
@@ -28,6 +28,7 @@ def test_1970(self):
             IsleOfMan(years=1970),
             ("1970-03-27", "Good Friday"),
             ("1970-03-30", "Easter Monday"),
+            ("1970-05-18", "Whit Monday"),
             ("1970-06-05", "TT Bank Holiday"),
             ("1970-07-05", "Tynwald Day"),
             ("1970-12-25", "Christmas Day"),
diff --git a/tests/countries/test_united_kingdom.py b/tests/countries/test_united_kingdom.py
index 690cb261c..02c2a850d 100644
--- a/tests/countries/test_united_kingdom.py
+++ b/tests/countries/test_united_kingdom.py
@@ -39,6 +39,14 @@ def test_country_aliases(self):
         self.assertAliases(UnitedKingdom, UK, GBR)
         self.assertAliases(UnitedKingdom, GB, GBR)
 
+    def test_no_holidays(self):
+        self.assertNoHolidays(UnitedKingdom(years=1870))
+        self.assertNoHolidays(UnitedKingdom(years=1870, subdiv="ENG"))
+        self.assertNoHolidays(UnitedKingdom(years=1870, subdiv="NIR"))
+        self.assertNoHolidays(UnitedKingdom(years=1870, subdiv="SCT"))
+        self.assertNoHolidays(UnitedKingdom(years=1870, subdiv="WLS"))
+        self.assertNoHoliday("1871-01-02", "1874-12-28")
+
     def test_special_holidays(self):
         self.assertHoliday(
             "1977-06-07",
@@ -208,6 +216,45 @@ def test_may_day(self):
         )
         self.assertNoHolidayName(name, range(1950, 1978))
 
+    def test_whit_monday(self):
+        name = "Whit Monday"
+        dt = (
+            "1950-05-29",
+            "1951-05-14",
+            "1952-06-02",
+            "1953-05-25",
+            "1954-06-07",
+            "1955-05-30",
+            "1956-05-21",
+            "1957-06-10",
+            "1958-05-26",
+            "1959-05-18",
+            "1960-06-06",
+            "1961-05-22",
+            "1962-06-11",
+            "1963-06-03",
+            "1964-05-18",
+            "1965-06-07",
+            "1966-05-30",
+            "1967-05-15",
+            "1968-06-03",
+            "1969-05-26",
+            "1970-05-18",
+        )
+        for subdiv in (
+            "ENG",
+            "NIR",
+            "WLS",
+            "England",
+            "Northern Ireland",
+            "Wales",
+        ):
+            self.assertHolidayName(name, self.subdiv_holidays[subdiv], dt)
+
+        for subdiv in ("SCT", "Scotland"):
+            self.assertNoHoliday(self.subdiv_holidays[subdiv], dt)
+            self.assertNoHolidayName(name, self.subdiv_holidays[subdiv], range(1950, 2050))
+
     def test_spring_bank_holiday(self):
         name = "Spring Bank Holiday"
         self.assertHolidayName(