A gimmick in English Pubs and clubs where the landlord or owner will reduce the price of the particular bevarage to £1 pound sterling per pint.

eg, Heineken is at a pound a pint. or all drinks are a pound a pint and £1.50 for shots

This often leads to hordes of extremely drunk students, charging through the streets, generally causing mayhem, the locals don't seem to like this too much.

However being able to get drunk on a fiver is an achievement that many seek, and in many large cities, you might even be able to do this every night except sunday.