Depending on where you dine/drink in the u.k, tipping is usually included in the bill. Last time I checked it was about ~7%. It's not a custom here, but the mark-up on most items makes you resent wanting to tip. When I was in the U.S prices on food/drink were substantially lower, and tipping wasn't an issue... but when you have to pay a fiver for a pint of watered down beer in London, you really dont want to tip anyone. /rant.
