What times is it in the U.K.?
Time zones in Britain and dealing with the 24-hour clock
The entire world actually sets it clocks by British time, since Great Brtiain is the keeper of the global standard of UTC (which stands for Coordinated Universal Time—or, at least, it does when you write it in French).
Practically speaking, however, the U.K. is five hours ahead of Eastern Standard Time.
That means when it's 1pm in New York and 10am in San Francisco, it's 6pm in London.
What about the rest of Europe?
Ireland, Portugal, and Iceland, are all also on GMT.
Most of the rest of Western Europe is one hour ahead of the U.K.
Greece, the easterly parts of Eastern Europe, and Finland are are all two hours ahead of GMT.
The Daylight Savings Time wrinkle
Since every country has its own date when daylight savings time kicks in, there are often brief periods when these differences shift by an hour.
Confusingly, GMT itself doesn't observe Daylight Savings Time, whereas the nations of the U.K. do, so during DST (from mid-spring to mid-autumn) all of Great Britain (save the Greenwich Royal Observatory) is on GMT +1.