UK is under BST (UTC+1) for half the year but people are usually just taught that the UK is GMT (UTC+0) which is based in the time in Greenwich, withought mentioning DST. I suppose it’s also possible everyone is taught BST and just forgets about it because daylight savings sucks, but either way most people seem to think GMT and UK time are the same thing.
This means you’ll get people asking for GMT times when they want BST or UK local time.