GBP Means Pounds, GBX Means Pence

Stock prices on the London Stock Exchange are quoted in pence, often referred to as GBX, occasionally referred to as GBp. Brokers usually report fees in pounds (GBP), so it's worth paying attention to the denomination. When entering transactions into an online portfolio most sites expect GBX for the share price of the transaction, and GBP for the fees and stamp duty (Google Finance is an exception, expecting GBX for both).

Recap: 1GBP = 100GBX