Charles Babbage 50p (2021)

With no circulating version, the Charles Babbage 50p is valued purely as a collector coin, and presentation and condition drive the price. Sealed in the original Royal Mint pack, it is worth more than a loose example or one in a capsule or third-party card. Scratches, fingermarks and spots on the open field lower the price, as does a damaged pack. The limited silver proof, piedfort and gold proof strikes of the Babbage design sit in a separate market.

The Charles Babbage 50p was not issued for circulation, so it has no rarity rank.

The design is made entirely of type: c h a r l e s and b a b b a g e in widely spaced small letters, with the digits 2 1 2 2 1 7 5 beneath them. There is no machine, portrait or scene. Queen Elizabeth II is on the heads side, above the year 2021. It was not released into circulation, so any found in change had been taken out of a pack.

Charles Babbage was an English mathematician and lifelong inventor who believed scientific progress should benefit everyone. He is best known for his calculating machines: the Difference Engine, a mechanical calculator, and the Analytical Engine, a design that anticipated many essential features of modern digital computers. The Royal Mint marked the 150th anniversary of his death in 2021 with the fourth coin of its Innovation in Science series, the first UK coin to celebrate him. Nigel Tudman and Jas Bhamra set out to link Babbage's machinery with the digital age, and they did it without a single picture. The reverse carries only type: his first name and surname in spaced lower-case letters, stacked on two lines, above a row of seven digits. Those digits are a simple code, giving the place in the alphabet of each letter of BABBAGE, so the surname appears twice, once in letters and once in numbers. The initials NT sit on the reverse, with the late Queen's fifth portrait, by Jody Clark, on the heads side.

It was one of the three coins in the Innovation in Science set issued in 2021.