diff --git a/imperial_coldfront_plugin/oidc.py b/imperial_coldfront_plugin/oidc.py
index 872f294..2fe35d1 100644
--- a/imperial_coldfront_plugin/oidc.py
+++ b/imperial_coldfront_plugin/oidc.py
@@ -1,30 +1,61 @@
 """Customisations for the OIDC authentication backend."""
 
+import logging
 from typing import Any
 
+from django.conf import settings
 from django.contrib.auth.models import User
 from mozilla_django_oidc.auth import OIDCAuthenticationBackend
 
+from .ldap import get_uid_from_ldap
+from .models import UnixUID
 
-def _update_user(user: User, claims: dict[str, Any]) -> None:
-    user.username = claims["preferred_username"].rstrip("@ic.ac.uk")
-    user.email = claims["email"]
-    user.first_name = claims["given_name"]
-    user.last_name = claims["family_name"]
-    user.save()
+logger = logging.getLogger("django")
 
 
 class ICLOIDCAuthenticationBackend(OIDCAuthenticationBackend):
     """Extension of the OIDC authentication backend for ICL auth."""
 
+    def _get_user_data_from_claims(self, claims: dict[str, Any]) -> dict[str, str]:
+        return dict(
+            username=claims["preferred_username"].rstrip("@ic.ac.uk"),
+            email=claims["email"],
+            first_name=claims["given_name"],
+            last_name=claims["family_name"],
+        )
+
+    def _update_user_from_dict(self, user: User, data: dict[str, str]) -> None:
+        user.username = data["username"]
+        user.email = data["email"]
+        user.first_name = data["first_name"]
+        user.last_name = data["last_name"]
+
     def create_user(self, claims: dict[str, Any]) -> User:
         """Create a new user from the available claims.
 
         Args:
           claims: user info provided by self.get_user_info
         """
+        user_data = self._get_user_data_from_claims(claims)
+        username = user_data["username"]
+        if settings.LDAP_SERVER_URI and settings.LDAP_SEARCH_BASE:
+            try:
+                uid = get_uid_from_ldap(username)
+            except Exception:
+                raise ValueError(
+                    f"Failed to retrieve UID from LDAP for user {username}"
+                )
+        else:
+            uid = None
+            logger.warn(
+                f"LDAP settings not configured, UID not retrieved for user {username}"
+            )
+
         user = super().create_user(claims)
-        _update_user(user, claims)
+        self._update_user_from_dict(user, user_data)
+        user.save()
+        if uid is not None:
+            UnixUID.objects.create(user=user, identifier=uid)
         return user
 
     def update_user(self, user: User, claims: dict[str, Any]) -> User:
@@ -34,7 +65,8 @@ def update_user(self, user: User, claims: dict[str, Any]) -> User:
           user: user to update
           claims: user info provided by self.get_user_info
         """
-        _update_user(user, claims)
+        user_data = self._get_user_data_from_claims(claims)
+        self._update_user_from_dict(user, user_data)
         return user
 
     def get_userinfo(