The Royal Mint has released a new collectable 50p coin to celebrate the life of British scientist and codebreaker Alan Turing.
Computer genius Turing is best known for breaking the German Enigma code during World War Two, leading to victory over Nazi Germany.
Historians believe he may have shortened the war by four years - saving tens of thousands of lives.
Turing already features on the new polymer £50 note - and now the Royal Mint are honouring him on a coin for the first time.
The 50p is available in gold, silver and base metal and was designed by artists Matt Dent and Christian Davies.
The reverse side of the coin features the name Alan Turing alongside an image of the Bombe machine used during the Second World War.
Do you have a rare coin in your collection? Let us know: mirror.money.saving@mirror.co.uk
In a special nod to his work, the designers have incorporated hidden word sequences as part of the 50p design.
Each one represents a Turing quote and significant location, as well as the designers’ initials.
The special coin can only be purchased from the Royal Mint as part of a collectable piece.
For now, the coin is uncirculated which means it won’t be widely released for use of everyday transactions.
As it isn’t being released into circulation, it is less likely you’ll find the Alan Turing 50p in your spare change - although not impossible, if someone were to spend one.
The cheapest coin is the Brilliant Uncirculated 50p and costs £10, while a Silver Proof version comes to £57.50 and is limited to 3,000.
The Royal Mint is also selling a Silver Proof Piedfort coin, limited to 1,500, for £102.50 - and the most expensive is the Gold Proof coin, costing £1,150 and limited to 180.
Each coin comes in a commemorative box or paper sleeve.
The coin is the final release in the Innovation is Science 50p series, which also features Charles Babbage, John Logie Baird, Rosalind Franklin and Stephen Hawking, and the Discovery of Insulin.
Nicola Howell, Chief Commercial Officer at The Royal Mint said: “Alan Turing was a scientific innovator whose work shaped Britain and it is fitting that his life and achievements will be commemorated for the first time on a collectable 50p.
“Made at the home of precious metals, where we have a rich heritage of British craftsmanship and innovation, the collectable Alan Turing coin will honour the father of computing in a range of gold, silver and base metal finishes.
“The release is the sixth and final 50p in the Innovation in Science collection and the design by Matt Dent and Christian Davies concludes the series brilliantly by incorporating hidden messages as part of the design, which we know is popular with collectors of the science series.”