diff --git a/scrapy/trunk/scrapy/utils/cookies.py b/scrapy/trunk/scrapy/utils/cookies.py
index 0d70fee10..156e72ad3 100644
--- a/scrapy/trunk/scrapy/utils/cookies.py
+++ b/scrapy/trunk/scrapy/utils/cookies.py
@@ -4,6 +4,7 @@ from cookielib import CookieJar as _CookieJar, DefaultCookiePolicy, Cookie
 class CookieJar(object):
     def __init__(self, policy=None):
         self.jar = _CookieJar(policy or DefaultCookiePolicy())
+        self.jar._cookies_jar = _DummyLock()
 
     def extract_cookies(self, response, request):
         wreq = WrappedRequest(request)
@@ -45,6 +46,14 @@ class CookieJar(object):
         self.jar.set_cookie_if_ok(cookie, WrappedRequest(request))
 
 
+class _DummyLock(object):
+    def acquire(self):
+        pass
+
+    def release(self):
+        pass
+
+
 class WrappedRequest(object):
     """Wraps a scrapy Request class with methods defined by urllib2.Request class to interact with CookieJar class