Index: Lib/imaplib.py
===================================================================
--- Lib/imaplib.py	(revision 88215)
+++ Lib/imaplib.py	(working copy)
@@ -1308,6 +1308,9 @@
 
 
 
+_month_names = ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun',
+                'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec']
+
 Mon2num = {'Jan': 1, 'Feb': 2, 'Mar': 3, 'Apr': 4, 'May': 5, 'Jun': 6,
         'Jul': 7, 'Aug': 8, 'Sep': 9, 'Oct': 10, 'Nov': 11, 'Dec': 12}
 
@@ -1401,14 +1404,11 @@
     else:
         raise ValueError("date_time not of a known type")
 
-    dt = time.strftime("%d-%b-%Y %H:%M:%S", tt)
-    if dt[0] == '0':
-        dt = ' ' + dt[1:]
     if time.daylight and tt[-1]:
         zone = -time.altzone
     else:
         zone = -time.timezone
-    return '"' + dt + " %+03d%02d" % divmod(zone//60, 60) + '"'
+    return '"' + '%02d-%s-%04d %02d:%02d:%02d' % (tt[2], _month_names[tt[1] - 1], tt[0], tt[3], tt[4], tt[5]) + ' %+03d%02d' % divmod(zone//60, 60) + '"'