A set of Alan Turing's papers failed to sell at auction at Christie's on Tuesday, meaning there is still a chance they could be snapped up by Bletchley Park campaigners.
Bids failed to make the reserve price for the lot, Christie's said.
The final bid for the lot was £240,000, according to the BBC's technology correspondent Rory Cellan-Jones, who was in the London auction room at the time. The Christie's list price for the lot was between £300,000 and £500,000.
"The lot didn't find a buyer," the auction house said.
What happens now "all depends on the agreement between Christie's and the seller", it added, and there is a possibility the lot could be sold in a private sale after the auction.
Earlier in the day, campaigners for the Bletchley Park Trust had struggled to raise funds so they could bid on the papers.