GBP is the abbreviation of Great British Pound. The pound, or sterling as it is also known, is the official currency of the United Kingdom and some of its overseas territories. It is also the currency used in UK crown dependencies the Channel Islands and the Isle of Man. There are numerous currencies which are pegged to the pound. These include the Guernsey pound, the Manx pound and the Gibraltar pound to name a few.
Sterling is one of the most widely traded currencies in the world after the US dollar, euro and Japanese yen. It accounts for around 13% of daily trading volume on global foreign exchange markets and is the oldest currency still being used as legal tender.