P:\test>set TZ=

P:\test>perl -le"print ~~localtime" & time /T
Tue Sep 14 10:49:05 2004
10:49

P:\test>set TZ=GMT

P:\test>perl -le"print ~~localtime" & time /T
Tue Sep 14 09:49:13 2004
10:49

P:\test>set TZ=BST

P:\test>perl -le"print ~~localtime" & time /T
Tue Sep 14 09:49:20 2004
10:49

P:\test>set TZ=GMT0BST

P:\test>perl -le"print ~~localtime" & time /T
Tue Sep 14 10:49:28 2004
10:49