'It's a once-in-a-lifetime discovery - not just for collectors, but for the sake of preserving the story of one of the greatest minds in history,' Jim Spencer, of Rare Books Auctions of Lichfield, Staffs, said.

Cache of Turing’s work was almost shredded after being discovered in a house clearance in London last year

The archive of papers included a signed copy of Turing’s 1939 PhD dissertation Systems Of Logic Based On Ordinals.

'It's a once-in-a-lifetime discovery - not just for collectors, but for the sake of preserving the story of one of the greatest minds in history,' Jim Spencer, of Rare Books…