At 02:00 BST on Sunday 29th October 2017 clocks will be retarded 1 hour to 01:00 GMT, time zone Zulu. (We don’t do UTC on this site.)
Clocks will remain on GMT until 01:00 Sunday 25th March 2018 when they will be advanced 1 hour to BST time zone Alpha
If you need to check your timepiece have a look HERE for a GMT clock.