Before 1971, Britain used pre-decimal money marked £sd: 12 pence to a shilling, 20 shillings to a pound. Everyday coins included the farthing, halfpenny, penny, threepence, sixpence, shilling, florin (two shillings) and half-crown (two-and-six), a system charming to collectors and maddening for arithmetic.

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On Decimal Day, 15 February 1971, the UK switched to a straightforward system of 100 new pence to the pound. New 5p and 10p coins (replacing the shilling and florin) had arrived earlier to ease the change, dual prices ran for a while, and the old coins were withdrawn as Britain standardised on the simpler decimal currency.