diff --git a/schemas/ispyb/updates/2025_04_29_DewarRegistry_fk_labContactId_on_delete_set_null.sql b/schemas/ispyb/updates/2025_04_29_DewarRegistry_fk_labContactId_on_delete_set_null.sql
new file mode 100644
index 0000000..863ebac
--- /dev/null
+++ b/schemas/ispyb/updates/2025_04_29_DewarRegistry_fk_labContactId_on_delete_set_null.sql
@@ -0,0 +1,12 @@
+INSERT IGNORE INTO SchemaStatus (scriptName, schemaStatus) VALUES ('2025_04_29_DewarRegistry_fk_labContactId_on_delete_set_null.sql', 'ONGOING');
+
+ALTER TABLE DewarRegistry
+  DROP CONSTRAINT DewarRegistry_ibfk_2;
+
+ALTER TABLE DewarRegistry
+  ADD CONSTRAINT DewarRegistry_ibfk_2
+    FOREIGN KEY (labContactId)
+      REFERENCES LabContact (labContactId)
+        ON DELETE SET NULL ON UPDATE CASCADE;
+
+UPDATE SchemaStatus SET schemaStatus = 'DONE' WHERE scriptName = '2025_04_29_DewarRegistry_fk_labContactId_on_delete_set_null.sql';