What is the currency of the United Kingdom?

The pound sterling, the oldest currency name still in use anywhere - over 1,200 years of continuous circulation. It began as a literal weight of silver divided into 240 pennies, which is why the symbol is a stylised L, for the Latin libra.

That is where the old money came from. Twelve pence to a shilling, twenty shillings to a pound, so 240 pence in total - awkward now and convenient then, because 240 divides evenly by 2, 3, 4, 5, 6, 8, 10, 12, 15, 16, 20 and more. Prices could be split many ways without fractions. Britain only decimalised in 1971, long after most of the world.

Sterling probably comes from the Old English for a small star stamped on early Norman pennies. What made it matter internationally was consistency: the English penny held its silver content unusually well for centuries, at a time when most rulers debased their coinage whenever they needed money, so a small island's currency became a trusted unit across northern Europe long before there was an empire behind it.