Index: django/http/__init__.py
===================================================================
--- django/http/__init__.py	(revision 4839)
+++ django/http/__init__.py	(working copy)
@@ -291,6 +291,11 @@
         HttpResponse.__init__(self, *args, **kwargs)
         self.status_code = 410
 
+class HttpResponseBadRequest(HttpResponse):
+    def __init__(self, *args, **kwargs):
+        HttpResponse.__init__(self, *args, **kwargs)
+        self.status_code = 400
+
 class HttpResponseServerError(HttpResponse):
     def __init__(self, *args, **kwargs):
         HttpResponse.__init__(self, *args, **kwargs)