New Banknote with Alan Turing: "This Is a Foretaste of What Is to Come, and the Shadow of What Is Going to Be"

Today is Alan Turing's birthday. More to the point, today the first £50 banknotes featuring Alan Turing will be issued. I wrote a bit about this when the design was announced in my post Computer Scientist Alan Turing to Be on British £50 Note. As a computer scientist by background, I think that it is great that one of the first computer scientists ever (well, he invented the Turing Machine) is honored in this way. The previous £50 note featured James Watt and Matthew Bolton, the inventors of the steam engine, one of the many innovations that ushered in the industrial revolution, first in the UK, then in many other countries. In the same way, I don''t think it is too far-fetched to draw a line from Turing's work on computation, through his work at Bletchley Park during the Second World War, to his work at Manchester after the war, and the ushering in of the computer revolution.

For those of you who live in the US, and many other countries, you've not seen a note like this. It is made of polymer (plastic) and features security windows that are transparent, making it impossible to simply reproduce on a photocopier or printer. ]t is the last note to be converted from paper to polymer  (there is no £100 note in Britain). The £5 note features Winston Churchill, the £10 features Jane Austen, and the £20 note features J.M.W. Turner. Not only are polymer notes more secure, they last longer. Britain is not that quick to this technology. It was originally developed in Australia and first used there.

But the Bank of England is very proud of their new note. Here are some of its features:

• It features a photo of Turing taken in 1951 by Elliott & Fry which is part of the Photographs Collection at the National Portrait Gallery.
• A table and mathematical formulae from Turing’s seminal 1936 paper “On Computable Numbers, with an application to the Entscheidungsproblem” Proceedings of the London Mathematical Society. This paper is widely recognized as being foundational for computer science. It sought to establish whether there could be a definitive method by which any theorem could be assessed as provable or not using a universal machine. It introduced the concept of a Turing machine as a thought experiment of how computers could operate.
• The Automatic Computing Engine (ACE) Pilot Machine which was developed at the National Physical Laboratory as the trial model of Turing’s pioneering ACE design. The ACE was one of the first electronic stored-program digital computers.
• Technical drawings for the British Bombe, the machine specified by Turing and one of the primary tools used to break Enigma-enciphered messages during WWII.
• A quote from Alan Turing, given in an interview to The Times newspaper on 11 June 1949: “This is only a foretaste of what is to come, and only the shadow of what is going to be.”
• Turing’s signature from the visitor’s book at Max Newman’s House in 1947 which is on display at Bletchley Park, where he worked during WWII.
• Ticker tape depicting Alan Turing’s birth date (23 June 1912) in binary code. The concept of a machine fed by binary tape featured in the Turing’s 1936 paper.
• A red foil patch containing the letters ‘AT’ is based on the image of a sunflower head linked to Turing’s morphogenetic work in later life.
• Security features:
  
  • A metallic hologram which changes between the words ‘Fifty’ and ‘Pounds’ when the note is tilted.
  • A large see-through window with a gold and green foil on the front depicting a finely detailed metallic microchip image.
  • There are two green 21 spiral features based on a sunflower head. The foil is silver on the back.
  • A metallic hologram which changes between the words ‘Fifty’ and ‘Pounds’ when the note is tilted.
  • A silver foil patch with a 3D image of the coronation crown.
  • The Queen’s portrait in the see-through window with ‘£50 Bank of England’ printed twice around the edge. (The small clover shapes on the outside of the window are based on architectural features at Bletchley Park.)
  • A smaller see-through window in the bottom corner of the note, the shape of which is based on architectural features at Bletchley Park.

Of course, in many ways, this note is already an anachronism since nobody pays cash for anything anymore, even before Covid made us all suspicious of pieces of paper where we didn't know where they had been.

Alan Turing in Breakfast Bytes

I mentioned my earlier post about Turing. He also shows up in three other Breakfast Bytes posts:

I have written before about Bletchley Park in my post British Computer Museums and I covered what happened after the war in "Lick" Licklider, Unsung Hero of US Computer Science. I was back at Bletchley Park a couple of years ago and wrote about that in my post Colossus: the First Programmable Digital Electronic Computer (although his appearance in that last post was to correct a misconception that Turing was the designer of Colossus).

Here's a paragraph to tempt you to read my earlier post when the fact that Turing would be on the £50 note was announced.

The British engineers, such as Turing, at Bletchley Park were even more unsung since, in what I consider an extremely shortsighted decision, the British destroyed all the machines at Bletchley Park and swore everyone to secrecy for 30 years. It set British computer science back by decades. I only discovered my great aunt worked at Bletchley Park after she died. My father says he thought she was just a typist, but with the post-war secrecy, the women were all told to say they were secretaries and typists as a cover story, so who knows? By the end of the war in 1945, 75% of the people at Bletchley Park were women.

Visit

As always, I recommend strongly visiting Bletchley Park. Full details are in the British Computer Museums post linked above. Obviously, if you don't live in Britain, first you have to get to London. But if travel gets back to anything like normal, that is not too far-fetched. And Bletchley railway station is a short train ride from London Euston, and the museum is about fifty yards walk away. Beware that there are two museums these days. The official Bletchley Park Museum is just the buildings ("huts") and around the corner is The British National Museum of Computing where the restored bombes and Colossus are housed, and the more technical story of the decoding operation is laid out.

And, of course, from today you can pay for your ticket in cash with a Turing £50 note!