A new £50 note featuring WW2 codebreaker Alan Turing has launched today - but you can only get your hands on the note in two locations.
Cash fans can find the notes in the City of London, near the Bank of England - or at Bletchley Post Office.
The Buckinghamshire Post Office branch has had a special delivery of the £50s because of the location's links with Turing.
He is best-known for his codebreaking work at Bletchley Park on cracking the German Enigma machine in WW2, which let the allies read secret enemy messages.
His work is credited with saving thousands of lives and shortening the course of the war.
Bletchley Post Office postmaster Ahmed Butt said: "It’s great that the town’s residents and visitors can get their hands on the new £50 note at our Post Office before it goes into wider circulation across the rest of the country.
"Many of my customers feel more comfortable dealing in cash and the great news is that anyone with the old £50 note can still come into Post Offices and deposit them into their bank account, even after the old note is withdrawn by the Bank of England.”
Today would also have been Turing's birthday.
The new £50s will be available all round the country from tomorrow.
The polymer £50 features Turing's portrait, designs for the British Bombe codebreaking device he helped make and some of his other mathematical formulae.
The Turing £50 has two translucent panels and a two-colour foil strip, making it tough to fake.
It also has a hologram image which changes between the words ‘fifty’ and ‘pounds’ when tilting the note from side to side.
The polymer banknotes are meant to last longer and be harder to forge than paper ones.
Turing, who was gay but engaged to a woman, Joan Clarke, was arrested in 1952 after an affair with a 19-year-old man.
Being gay only stopped being a crime in 1967. Turing was forced to take female hormones, so-called 'chemical castration', or else go to prison.
He killed himself in 1954 and got a royal pardon for his 'crime' in 2013.
Post Office retail & franchise network director Amanda Jones said: “What happened less than a mile away at Bletchley Park helped end WW2, and Alan Turing played such a pivotal role as a codebreaker."
You can keep using the current paper £50 notes as usual. They will be withdrawn, but the Bank of England will give at least six months' notice before they are.
Many people have never even seen a £50 note. Cash machines rarely give them out and they are too high-value to appear regularly in your change.
But there are still 357 million £50 notes in circulation - almost as many as £5 notes (407 million).
The current paper £50 was issued in 2011 and features James Watt and Matthew Boulton, who designed the steam engine.
Paper notes were first introduced by the Bank of England in 1694.
