diff --git a/backend/condition/lookups/uprn_lookup.py b/backend/condition/lookups/uprn_lookup.py
new file mode 100644
index 00000000..be8535bd
--- /dev/null
+++ b/backend/condition/lookups/uprn_lookup.py
@@ -0,0 +1,7 @@
+from abc import ABC, abstractmethod
+from typing import Dict
+
+
+class UprnLookup(ABC):
+    def get_location_ref_to_uprn_map() -> Dict[str, int]:
+        pass
diff --git a/backend/condition/lookups/uprn_lookup_local.py b/backend/condition/lookups/uprn_lookup_local.py
new file mode 100644
index 00000000..bb4962e5
--- /dev/null
+++ b/backend/condition/lookups/uprn_lookup_local.py
@@ -0,0 +1,7 @@
+from typing import Dict
+from backend.condition.lookups.uprn_lookup import UprnLookup
+
+
+class UprnLookupLocal(UprnLookup):
+    def get_location_ref_to_uprn_map() -> Dict[str, int]:
+        raise NotImplementedError
diff --git a/backend/condition/lookups/uprn_lookup_s3.py b/backend/condition/lookups/uprn_lookup_s3.py
new file mode 100644
index 00000000..83d6032c
--- /dev/null
+++ b/backend/condition/lookups/uprn_lookup_s3.py
@@ -0,0 +1,7 @@
+from typing import Dict
+from backend.condition.lookups.uprn_lookup import UprnLookup
+
+
+class UprnLookupS3(UprnLookup):
+    def get_location_ref_to_uprn_map() -> Dict[str, int]:
+        raise NotImplementedError