GMT has always zero offset from UTC. During daylight saving, the UK switches to another time zone called BST, with an offset of +1h. Other countries might call

GMT has always zero offset from UTC. During daylight saving, the UK switches to another time zone called BST, with an offset of +1h. Other countries might call their summer time zone with a different name. UTC != GMT because the former is not a time zone but a time standard. No country uses UTC as a time zone because UTC is not a time zone. All times in the GMT time zone are numerically equal to times expressed in UTC though.