diff --git a/CHANGELOG.md b/CHANGELOG.md
index bdc79891..b43d3841 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,8 @@ The format is based on [Keep a Changelog 1.0.0].
 
 ## [Unreleased]
 
+- **Breaking:**: Fully remove the deprecated `caselawclient.api_client` instance.
+
 ## [Release 17.3.0]
 
 - **Feature:** `Document.enrich()` method will send a message to the announce SNS, requesting that a document be enriched.
diff --git a/src/caselawclient/Client.py b/src/caselawclient/Client.py
index a1347379..2622fbca 100644
--- a/src/caselawclient/Client.py
+++ b/src/caselawclient/Client.py
@@ -951,17 +951,3 @@ def get_combined_stats_table(self) -> list[list[Any]]:
         )
 
         return results
-
-
-api_client = MarklogicApiClient(
-    host=env("MARKLOGIC_HOST", default=None),
-    username=env("MARKLOGIC_USER", default=None),
-    password=env("MARKLOGIC_PASSWORD", default=None),
-    use_https=env("MARKLOGIC_USE_HTTPS", default=False),
-)
-"""
-An instance of the API client which is automatically initialised on importing the library.
-
-.. deprecated:: 13.0.1
-   You should instead initialise your own instance of `MarklogicApiClient`
-"""
diff --git a/src/caselawclient/__init__.py b/src/caselawclient/__init__.py
index 08e5d701..e9b5ed0b 100644
--- a/src/caselawclient/__init__.py
+++ b/src/caselawclient/__init__.py
@@ -37,24 +37,4 @@
 
 ```
 
-## (Deprecated) Use in-library client instance
-
-This library will automatically initialise an instance of the client. This functionality is deprecated, and will be
-removed.
-
-The client expects the following environment variables to be set or defined in a `.env` file:
-
-```bash
-MARKLOGIC_HOST
-MARKLOGIC_USER
-MARKLOGIC_PASSWORD
-MARKLOGIC_USE_HTTPS # Optional, defaults to False
-```
-
-Then import `api_client` from `caselawclient.Client`:
-
-```python
-from caselawclient.Client import api_client
-```
-
 """
diff --git a/src/caselawclient/client_helpers/search_helpers.py b/src/caselawclient/client_helpers/search_helpers.py
index 4e70b200..cc4726f9 100644
--- a/src/caselawclient/client_helpers/search_helpers.py
+++ b/src/caselawclient/client_helpers/search_helpers.py
@@ -1,3 +1,5 @@
+from lxml import etree
+
 from caselawclient.Client import MarklogicApiClient
 from caselawclient.responses.search_response import SearchResponse
 from caselawclient.search_parameters import SearchParameters
@@ -14,8 +16,11 @@ def search_judgments_and_parse_response(
 
     :return: The parsed search response as a SearchResponse object
     """
-    return SearchResponse.from_response_string(
-        api_client.search_judgments_and_decode_response(search_parameters)
+    return SearchResponse(
+        etree.fromstring(
+            api_client.search_judgments_and_decode_response(search_parameters)
+        ),
+        api_client,
     )
 
 
@@ -30,6 +35,7 @@ def search_and_parse_response(
 
     :return: The parsed search response as a SearchResponse object
     """
-    return SearchResponse.from_response_string(
-        api_client.search_and_decode_response(search_parameters)
+    return SearchResponse(
+        etree.fromstring(api_client.search_and_decode_response(search_parameters)),
+        api_client,
     )
diff --git a/src/caselawclient/responses/search_response.py b/src/caselawclient/responses/search_response.py
index 51c57162..f5cf034c 100644
--- a/src/caselawclient/responses/search_response.py
+++ b/src/caselawclient/responses/search_response.py
@@ -2,6 +2,7 @@
 
 from lxml import etree
 
+from caselawclient.Client import MarklogicApiClient
 from caselawclient.responses.search_result import SearchResult
 
 
@@ -13,22 +14,14 @@ class SearchResponse:
     NAMESPACES = {"search": "http://marklogic.com/appservices/search"}
     """ Namespaces used in XPath expressions."""
 
-    def __init__(self, node: etree._Element) -> None:
+    def __init__(self, node: etree._Element, client: MarklogicApiClient) -> None:
         """
         Initializes a SearchResponse instance from an xml node.
 
         :param node: The XML data as an etree element
         """
         self.node = node
-
-    @staticmethod
-    def from_response_string(xml: str) -> "SearchResponse":
-        """
-        Constructs a SearchResponse instance from an xml response string.
-
-        :param xml: The XML data as a string
-        """
-        return SearchResponse(etree.fromstring(xml))
+        self.client = client
 
     @property
     def total(self) -> str:
@@ -51,9 +44,4 @@ def results(self) -> List[SearchResult]:
         results = self.node.xpath(
             "//search:response/search:result", namespaces=self.NAMESPACES
         )
-        return [
-            SearchResult(
-                result,
-            )
-            for result in results
-        ]
+        return [SearchResult(result, self.client) for result in results]
diff --git a/src/caselawclient/responses/search_result.py b/src/caselawclient/responses/search_result.py
index 5bafc45c..629409b7 100644
--- a/src/caselawclient/responses/search_result.py
+++ b/src/caselawclient/responses/search_result.py
@@ -2,6 +2,7 @@
 import os
 from datetime import datetime
 from enum import Enum
+from functools import cached_property
 from typing import Dict, Optional
 
 from dateutil import parser as dateparser
@@ -9,7 +10,7 @@
 from ds_caselaw_utils.courts import Court, CourtNotFoundException, courts
 from lxml import etree
 
-from caselawclient.Client import api_client
+from caselawclient.Client import MarklogicApiClient
 from caselawclient.models.documents import DocumentURIString
 from caselawclient.xml_helpers import get_xpath_match_string
 
@@ -44,20 +45,6 @@ def __init__(self, node: etree._Element, last_modified: str):
         self.node = node
         self.last_modified = last_modified
 
-    @staticmethod
-    def create_from_uri(uri: DocumentURIString) -> "SearchResultMetadata":
-        """
-        Create a SearchResultMetadata instance from a search result URI.
-
-        :param uri: The URI of the search result
-
-        :return: The created SearchResultMetadata instance
-        """
-        response_text = api_client.get_properties_for_search_results([uri])
-        last_modified = api_client.get_last_modified(uri)
-        root = etree.fromstring(response_text)
-        return SearchResultMetadata(root, last_modified)
-
     @property
     def author(self) -> str:
         """
@@ -162,12 +149,13 @@ class SearchResult:
     }
     """ Namespace mappings used in XPath expressions. """
 
-    def __init__(self, node: etree._Element):
+    def __init__(self, node: etree._Element, client: MarklogicApiClient):
         """
         :param node: The XML element representing the search result
         """
 
         self.node = node
+        self.client = client
 
     @property
     def uri(self) -> DocumentURIString:
@@ -259,15 +247,15 @@ def matches(self) -> str:
         xslt_transform = etree.XSLT(etree.parse(file_path))
         return str(xslt_transform(self.node))
 
-    @property
+    @cached_property
     def metadata(self) -> SearchResultMetadata:
         """
-        :return: The metadata of the search result
+        :return: A `SearchResultMetadata` instance representing the metadata of this result
         """
-
-        return SearchResultMetadata.create_from_uri(
-            self.uri,
-        )
+        response_text = self.client.get_properties_for_search_results([self.uri])
+        last_modified = self.client.get_last_modified(self.uri)
+        root = etree.fromstring(response_text)
+        return SearchResultMetadata(root, last_modified)
 
     def _get_xpath_match_string(self, path: str) -> str:
         return get_xpath_match_string(self.node, path, namespaces=self.NAMESPACES)
diff --git a/tests/client/test_search_and_decode_response.py b/tests/client/test_search_and_decode_response.py
index 62a1a515..eb235e91 100644
--- a/tests/client/test_search_and_decode_response.py
+++ b/tests/client/test_search_and_decode_response.py
@@ -1,61 +1,71 @@
 from unittest.mock import patch
 
-from caselawclient.Client import api_client
+from caselawclient.Client import MarklogicApiClient
 from caselawclient.search_parameters import SearchParameters
 
 
-@patch("caselawclient.Client.api_client.advanced_search")
-def test_search_judgments_and_decode_response(
-    mock_advanced_search,
-    valid_search_response_xml,
-    generate_mock_search_response,
-):
-    """
-    Given the search parameters for search_judgments_and_decode_response are valid
-    And a mocked api_client response with search results
-    When search_judgments_and_decode_response function is called with the mocked API client
-        and input parameters
-    Then the API client's advanced_search method should be called once with the
-        appropriate parameters
-    And the search_judgments_and_decode_response function should return the response
-        xml string with all the search results
-    """
-    mock_advanced_search.return_value = generate_mock_search_response(
-        valid_search_response_xml
-    )
-
-    search_response = api_client.search_judgments_and_decode_response(
-        SearchParameters(
-            query="test query",
-            court="test court",
-            judge="test judge",
-            party="test party",
-            neutral_citation="test citation",
-            specific_keyword="test keyword",
-            date_from="2022-01-01",
-            date_to="2022-01-31",
-            page=1,
-            page_size=10,
+class TestSearchAndDecodeResponse:
+    def setup_method(self):
+        self.client = MarklogicApiClient(
+            host="",
+            username="",
+            password="",
+            use_https=False,
+            user_agent="marklogic-api-client-test",
         )
-    )
 
-    mock_advanced_search.assert_called_once_with(
-        SearchParameters(
-            query="test query",
-            court="test court",
-            judge="test judge",
-            party="test party",
-            neutral_citation="test citation",
-            specific_keyword="test keyword",
-            order=None,
-            date_from="2022-01-01",
-            date_to="2022-01-31",
-            page=1,
-            page_size=10,
-            show_unpublished=False,
-            only_unpublished=False,
-            collections=["judgment"],
-        )
-    )
+    def test_search_judgments_and_decode_response(
+        self,
+        valid_search_response_xml,
+        generate_mock_search_response,
+    ):
+        """
+        Given the search parameters for search_judgments_and_decode_response are valid
+        And a mocked MarklogicApiClient.advanced_search response with search results
+        When search_judgments_and_decode_response function is called with the mocked API client
+            and input parameters
+        Then the API client's advanced_search method should be called once with the
+            appropriate parameters
+        And the search_judgments_and_decode_response function should return the response
+            xml string with all the search results
+        """
+        with patch.object(self.client, "advanced_search") as mock_advanced_search:
+            mock_advanced_search.return_value = generate_mock_search_response(
+                valid_search_response_xml
+            )
+
+            search_response = self.client.search_judgments_and_decode_response(
+                SearchParameters(
+                    query="test query",
+                    court="test court",
+                    judge="test judge",
+                    party="test party",
+                    neutral_citation="test citation",
+                    specific_keyword="test keyword",
+                    date_from="2022-01-01",
+                    date_to="2022-01-31",
+                    page=1,
+                    page_size=10,
+                )
+            )
+
+            mock_advanced_search.assert_called_once_with(
+                SearchParameters(
+                    query="test query",
+                    court="test court",
+                    judge="test judge",
+                    party="test party",
+                    neutral_citation="test citation",
+                    specific_keyword="test keyword",
+                    order=None,
+                    date_from="2022-01-01",
+                    date_to="2022-01-31",
+                    page=1,
+                    page_size=10,
+                    show_unpublished=False,
+                    only_unpublished=False,
+                    collections=["judgment"],
+                )
+            )
 
-    assert search_response == valid_search_response_xml
+            assert search_response == valid_search_response_xml
diff --git a/tests/responses/test_search_response.py b/tests/responses/test_search_response.py
index 4227d8eb..c99a2369 100644
--- a/tests/responses/test_search_response.py
+++ b/tests/responses/test_search_response.py
@@ -1,10 +1,20 @@
 import pytest
 from lxml import etree
 
+from caselawclient.Client import MarklogicApiClient
 from caselawclient.responses.search_response import SearchResponse
 
 
 class TestSearchResponse:
+    def setup_method(self):
+        self.client = MarklogicApiClient(
+            host="",
+            username="",
+            password="",
+            use_https=False,
+            user_agent="marklogic-api-client-test",
+        )
+
     def test_total(
         self,
     ):
@@ -13,10 +23,13 @@ def test_total(
         When calling 'total' on it
         Then it should return a string representing the total number of results
         """
-        search_response = SearchResponse.from_response_string(
-            '<search:response xmlns:search="http://marklogic.com/appservices/search" total="5">'  # noqa: E501
-            "foo"
-            "</search:response>"
+        search_response = SearchResponse(
+            etree.fromstring(
+                '<search:response xmlns:search="http://marklogic.com/appservices/search" total="5">'  # noqa: E501
+                "foo"
+                "</search:response>"
+            ),
+            self.client,
         )
 
         assert search_response.total == "5"
@@ -32,8 +45,9 @@ def test_results(
         Then it should return a list of n SearchResult elements
         And each element's node attribute should be as expected
         """
-        search_response = SearchResponse.from_response_string(
-            generate_search_response_xml(2 * valid_search_result_xml)
+        search_response = SearchResponse(
+            etree.fromstring(generate_search_response_xml(2 * valid_search_result_xml)),
+            self.client,
         )
 
         results = search_response.results
@@ -64,4 +78,4 @@ def test_when_search_namespace_prefix_not_defined_on_response_xml_syntax_error_r
             etree.XMLSyntaxError,
             match="Namespace prefix search on response is not defined",
         ):
-            SearchResponse.from_response_string(xml_without_namespace)
+            SearchResponse(etree.fromstring(xml_without_namespace), self.client)
diff --git a/tests/responses/test_search_result.py b/tests/responses/test_search_result.py
index b4e698cd..3b7c8f0f 100644
--- a/tests/responses/test_search_result.py
+++ b/tests/responses/test_search_result.py
@@ -5,6 +5,7 @@
 from ds_caselaw_utils.courts import Court
 from lxml import etree
 
+from caselawclient.Client import MarklogicApiClient
 from caselawclient.responses.search_result import (
     EditorPriority,
     EditorStatus,
@@ -14,32 +15,46 @@
 
 
 class TestSearchResult:
-    @patch("caselawclient.responses.search_result.api_client")
-    def test_init(self, mock_api_client, valid_search_result_xml):
+    def setup_method(self):
+        self.client = MarklogicApiClient(
+            host="",
+            username="",
+            password="",
+            use_https=False,
+            user_agent="marklogic-api-client-test",
+        )
+
+    def test_init(self, valid_search_result_xml):
         """
         GIVEN a valid search result XML and a mock API client
         WHEN initializing a SearchResult object
         THEN the attributes are set correctly
         """
-        mock_api_client.get_properties_for_search_results.return_value = "<foo/>"
-        mock_api_client.get_last_modified.return_value = "bar"
-
-        node = etree.fromstring(valid_search_result_xml)
-        search_result = SearchResult(node)
-
-        assert search_result.uri == "a/c/2015/20"
-        assert search_result.neutral_citation == "[2015] A 20 (C)"
-        assert search_result.name == "Another made up case name"
-        assert search_result.date == datetime.datetime(2017, 8, 8, 0, 0)
-        assert search_result.court is None
-        assert search_result.matches == (
-            "<p data-path=\"fn:doc('/a/c/2015/20.xml')/*:akomaNtoso\">"
-            "text from the document that matched the search</p>\n"
-        )
-        assert search_result.content_hash == "test_content_hash"
-        assert search_result.transformation_date == "2023-04-09T18:05:45"
-        assert etree.tostring(search_result.metadata.node).decode() == "<foo/>"
-        assert search_result.metadata.last_modified == "bar"
+        with (
+            patch.object(
+                self.client, "get_properties_for_search_results"
+            ) as mock_get_properties_for_search_results,
+            patch.object(self.client, "get_last_modified") as mock_get_last_modified,
+        ):
+            mock_get_properties_for_search_results.return_value = "<foo/>"
+            mock_get_last_modified.return_value = "bar"
+
+            node = etree.fromstring(valid_search_result_xml)
+            search_result = SearchResult(node, self.client)
+
+            assert search_result.uri == "a/c/2015/20"
+            assert search_result.neutral_citation == "[2015] A 20 (C)"
+            assert search_result.name == "Another made up case name"
+            assert search_result.date == datetime.datetime(2017, 8, 8, 0, 0)
+            assert search_result.court is None
+            assert search_result.matches == (
+                "<p data-path=\"fn:doc('/a/c/2015/20.xml')/*:akomaNtoso\">"
+                "text from the document that matched the search</p>\n"
+            )
+            assert search_result.content_hash == "test_content_hash"
+            assert search_result.transformation_date == "2023-04-09T18:05:45"
+            assert etree.tostring(search_result.metadata.node).decode() == "<foo/>"
+            assert search_result.metadata.last_modified == "bar"
 
     def test_create_from_node_with_unparsable_date(self):
         """
@@ -55,7 +70,7 @@ def test_create_from_node_with_unparsable_date(self):
             "</search:result>"
         )
         node = etree.fromstring(xml)
-        search_result = SearchResult(node)
+        search_result = SearchResult(node, self.client)
 
         assert search_result.date is None
 
@@ -73,7 +88,7 @@ def test_create_from_node_with_valid_court_code(self):
             "</search:result>"
         )
         node = etree.fromstring(xml)
-        search_result = SearchResult(node)
+        search_result = SearchResult(node, self.client)
 
         assert isinstance(search_result.court, Court)
         assert search_result.court.name == "United Kingdom Supreme Court"
@@ -92,7 +107,7 @@ def test_create_from_node_with_invalid_court_code(self):
             "</search:result>"
         )
         node = etree.fromstring(xml)
-        search_result = SearchResult(node)
+        search_result = SearchResult(node, self.client)
 
         assert search_result.date is None
 
@@ -188,36 +203,6 @@ def test_editor_status(
 
         assert meta.editor_status == expected_editor_status.value
 
-    @patch("caselawclient.responses.search_result.api_client")
-    def test_create_from_uri(self, mock_api_client):
-        """
-        GIVEN a uri and a mock API client
-        WHEN SearchResultMetadata.create_from_uri is called with the uri
-        THEN a SearchResultMetadata object is returned with expected attributes
-        """
-        mock_api_client.get_properties_for_search_results.return_value = (
-            "<property-results>"
-            "<property-result>"
-            "<assigned-to>test_assigned_to</assigned-to>"
-            "<source-name>test_author</source-name>"
-            "<source-email>test_author_email</source-email>"
-            "<transfer-consignment-reference>test_consignment_reference</transfer-consignment-reference>"
-            "<editor-hold>false</editor-hold>"
-            "<editor-priority>30</editor-priority>"
-            "<transfer-received-at>2023-01-26T14:17:02Z</transfer-received-at>"
-            "</property-result>"
-            "</property-results>"
-        )
-        mock_api_client.get_last_modified.return_value = "test_last_modified"
-
-        meta = SearchResultMetadata.create_from_uri("test_uri")
-
-        assert (
-            etree.tostring(meta.node).decode()
-            == mock_api_client.get_properties_for_search_results.return_value
-        )
-        assert meta.last_modified == "test_last_modified"
-
     def test_submission_date_is_min_when_transfer_received_at_empty(self):
         """
         GIVEN a node where the `transfer-received-at` element is empty