diff --git a/gateway/delivery_ledger.py b/gateway/delivery_ledger.py
index 675ce4e4fa..d83738bc74 100644
--- a/gateway/delivery_ledger.py
+++ b/gateway/delivery_ledger.py
@@ -523,15 +523,6 @@ def _prune_unlocked(conn, now: float) -> None:
                  LIMIT ?)""", (total - _MAX_ROWS,))
 
 
-def _prune(now: Optional[float] = None) -> None:
-    now = now if now is not None else time.time()
-    try:
-        with _transaction() as conn:
-            _prune_unlocked(conn, now)
-    except Exception:
-        logger.debug("delivery ledger prune failed", exc_info=True)
-
-
 def ledger_enabled(config: Optional[Dict[str, Any]] = None) -> bool:
     """Read the ``gateway.delivery_ledger`` config gate (default on)."""
     try:
diff --git a/tests/gateway/test_delivery_ledger.py b/tests/gateway/test_delivery_ledger.py
index f07b9da7eb..316a649b26 100644
--- a/tests/gateway/test_delivery_ledger.py
+++ b/tests/gateway/test_delivery_ledger.py
@@ -376,7 +376,9 @@ class TestPrune:
                 "UPDATE delivery_obligations SET updated_at=? WHERE obligation_id=?",
                 (time.time() - dl._RETENTION_SECONDS - 60, "ob-1"),
             )
-        dl._prune()
+        # Prune has no wrapper of its own: it runs inside a writer's transaction, lock held.
+        with dl._DB_LOCK, dl._transaction() as conn:
+            dl._prune_unlocked(conn, time.time())
         assert _row("ob-1") is None