£50 note

Hologram

Tilt the note from side to side. Check the words change between 'Fifty' and 'Pounds'. 

Within the two gold foil squares on the front of the £50 note, the images change between ‘50’ and a ‘£’ symbol when the note is tilted.

See through windows

Look at the metallic image over the main window. Check the foil is gold and green on the front of the note and silver on the back. Look for a second, smaller window in the bottom corner of the note.

Tactile feature

On the front of the note (the side with raised print), there are four clusters of raised dots in the top left hand corner. This tactile feature helps blind and partially sighted people identify the value of the note.

Size

The higher the value of a note, the larger it is. This note is approximately 146mm x 77mm.

Unique numbering

A unique serial number is printed horizontally and vertically on the back of the note. The horizontal number is in the bottom right corner. It is made up of multi-coloured letters and numbers, which increase in height from left to right. The vertical number runs down the left-hand side and the numbers and letters are the same height and colour.

Copyright symbols

The international copyright symbol is included on the front and back of the note, below the ‘Fifty Pounds’ text.

Historical character

Alan Turing's portrait is based on a photo taken in 1951 by Elliott & Fry which is part of the Photographs Collection at the National Portrait Gallery.

Alan Turing provided the theoretical underpinnings for the modern computer. While best known for his work devising code-breaking machines during WWII, Turing played a pivotal role in the development of early computers first at the National Physical Laboratory and later at the University of Manchester. He set the foundations for work on artificial intelligence by considering the question of whether machines could think. Turing was homosexual and was posthumously pardoned by HM Queen Elizabeth II having been convicted of gross indecency for his relationship with a man. His legacy continues to have an impact on both science and society today.

Artwork

The design on the reverse of the note celebrates Alan Turing and his pioneering work with computers. It features:

• A mathematical table and 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 recognised as being foundational for computer science.
• 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.
• Ticker tape depicting Alan Turing’s birth date (23 June 1912) in binary code. 
• 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. 
• The flower-shaped red foil patch on the back of the note is based on the image of a sunflower head linked to Turing’s morphogenetic (study of patterns in nature) work in later life.
• A series of background images, depicting technical drawings from The ACE Progress Report.

Quote

"This is only a foretaste of what is to come and only the shadow of what is going to be" is a quote from Alan Turing, given in an interview to The Times newspaper on 11 June 1949.

Signature

Turing's signature has been taken from the visitor's signature book on display at Bletchley Park Trust in 1947, where he worked during WWII.