Until 1872, the currency situation in Gibraltar was complicated, with a system based on the real being employed which encompassed British, Spanish and Gibraltarian coins. From 1825, the real (actually the Spanish real de plata) was tied to the pound at the rate of 1 Spanish dollar to 4 shillings 4 pence (equivalent to 21.67 pence today). In 1872, however, the Spanish currency became the sole legal tender in Gibraltar. In 1898, the Spanish–American War made the Spanish peseta drop alarmingly and the pound was introduced as the sole currency of the colony, initially in the form of British coins and banknotes.
In 1898, the British pound was made sole legal tender, although the Spanish peseta continued in circulation until the Spanish Civil War. Since 1927, Gibraltar has issued its own banknotes and, since 1988, its own coins. Gibraltar decimalised in 1971 at the same time as the UK, replacing the system of 1 pound = 20 shillings = 240 pence with one of 1 pound = 100 (new) pence.
The Currency Notes Act of 1934 confers on the Government of Gibraltar the right to print its own notes, and the obligation to back and exchange each printed note with sterling reserves at a rate of one pound to one pound sterling. Although Gibraltar notes are denominated in "pounds sterling", they are not legal tender in the United Kingdom, but they are in theory exchangeable at par for British notes at banks; in practice, UK high street banks will not accept or exchange Sterling notes issued by the Government of Gibraltar as they are deemed to be a foreign currency, although some will do so at below par, as with most currency exchange. Gibraltar's coins are the same weight, size and metal as UK coins, although the designs are different, and they are occasionally found in circulation across Britain.
In 1988, coins in denominations of 1, 2, 5, 10, 20 and 50 pence and 1 pound were introduced which bore specific designs for and the name of Gibraltar. They were the same sizes and compositions as the corresponding British coins, with 2 pound coins introduced in 1999. A new coin of 5 pounds was issued in 2010 with the inscription "Elizabeth II · Queen of Gibraltar".
At the outbreak of World War I, Gibraltar was forced to issue banknotes to prevent paying out sterling or gold. These notes were issued under emergency wartime legislation, Ordinance 10 of 1914. At first the typeset notes were signed by hand by Treasurer Greenwood, though he later used stamps. The notes bore the embossed stamp of the Anglo-Egyptian Bank Ltd. and circulated alongside British Territory notes. The 1914 notes were issued in denominations of 2 and 10 shillings, 1, 5 and 50 pounds. The 2 shilling and 50 pound notes were not continued when a new series of notes was introduced in 1927. The 10 shilling note was replaced by the 50 pence coin during the process of decimalization. In 1975, 10 and 20 pound notes were introduced, followed by 50 pounds in 1986. The 1 pound note was discontinued in 1988. In 1995, a new series of notes was introduced which, for the first time, bore the words "pounds sterling" rather than just "pounds". The government of Gibraltar introduced a new series of banknotes beginning with the 10 and 50 pound sterling notes issued on July 8, 2010. On May 11, 2011, the 5, 20 and 100 pound sterling notes were issued.