I've lost count of the discussions I've had over this issue at our pub. We have pricing for 7oz, 12oz, handles (16oz) and pints (20oz) on a chalkboard.
Basically a handle is a US pint and the UK pint is 20oz. Most peple don't know the difference and usually when someone askes for a 'pint' there's ofetn confusion when we lift two different glasses up and say "which one?".