Try to click the Reload or Refresh button on your browser, and see if that helps. If it does not help, try to click that button while pressing the Shift-key on your keyboard.
This problem is usually because you are looking at an old version of the page, that has been cached somewhere, either in your browser, your firewall or proxyserver, so you are actually looking at an old version. Reloading the page should fix the problem. You could also try using this link: World Clock. If you think there is some city that has the wrong time, please send an email describing why you believe it is wrong.
UTC - Universal Coordinated Time - is the standard time zone, which the other time zones are based upon. It never observes daylight saving time. The local time in Great Britain in the winter is called Greenwich Mean Time (GMT). However, in the summer, Great Britain is not on GMT, but one hour ahead, on British Summer Time (BST), or UTC+1. So if you are looking for/comparing with time in Great Britain, please use London as your reference, and not UTC.