About.com reports that the legal currency in London is the pound sterling. The official London visitor's site notes that despite being a member of the European Union, the United Kingdom does not use the Euro as standard currency.
According to the official London visitor's site, the pound is denoted by GBP. The pound comes in both bill and coin denominations. The official London visitor's site lists bill denominations as 5, 10, 20 and 50 pound notes. Coins appear in either pence or pound denominations. These denominations are 1p, 2p, 5p, 10p, 20p, 50p, 1 GBP and 2 GBP. About.com notes that residents of London may refer to 1 GBP as a "quid" or "nicker" colloquially. One pound sterling is equal to 100 pence.