The Biafran pound was the currency of the breakaway Republic of Biafra between 1968 and 1970.
The first notes denominated in 5 shillings and £1 were introduced on January 29, 1968. A series of coins was issued in 1969; 3 pence, 6 pence, 1 shilling and 2½ shilling coins were minted, all made of aluminium. In February 1969, a second family of notes was issued consisting of 5 shilling, 10 shilling, £1, £5 and £10 denominations. Despite not being recognised as currency by the rest of the world when they were issued, the banknotes were afterwards sold as curios (typically at 2/6 (=.0125 GBP) for 1 pound notes in London philately/notaphily shops) and are now traded among banknote collectors at well above their original nominal value.
The most common note is the 1968 1 pound, with the 10 pound and all coins being rare.