diff --git a/synapse/storage/_base.py b/synapse/storage/_base.py
index b6f8817b6..1967290ad 100644
--- a/synapse/storage/_base.py
+++ b/synapse/storage/_base.py
@@ -23,7 +23,6 @@ from synapse.util.logcontext import PreserveLoggingContext, LoggingContext
 from twisted.internet import defer
 
 import collections
-import copy
 import json
 import sys
 import time