Formerly classified documents connected to the D-day landings are being auctioned in Northamptonshire as part of an international militaria sale.
The set of administrative order files for Operation Neptune, part of the Operation Overlord campaign, date back to May 18, 1944.
The Allied mission was the first stage of the invasion of Normandy, involving over 5,000 vessels from eight different naval fleets.
More than 60 typed pages of detailed information about the battle, procedures, weapons, codenames, mines and booby traps are included in the lot along with several hand drawn maps and diagrams of vessels and communication networks.
Last year an Operation Overlord map sold for £1,300, but this current bundle of documents is expected to sell for between £8,000 and £10,000.
The files are being put up for auction by J P Humbert Auctioneers at its Silverstone Business Park premises, on Tuesday, September 22.
Auctioneer Jonathan Humbert was given the document, belonging to his grandfather, by a distant family member.
He said: “I am delighted and honoured to be offering for sale this incredibly rare and beyond top secret, now declassified, document of my late grandfather.
“I never knew he was so heavily involved in Operation Overlord - he was very modest about his wartime exploits, although I know he was shot in the arm while having a bath and later received the Territorial Decoration.”
The D-Day files being auctioned were given the “BIGOT” classification, given to only the highest security files.
“BIGOT” was a code word that had two meanings.
Spelt backwards it reveals “TO GIB”, a phrase that was stamped on papers of officers going to Gibraltar for the 1942 invasion of North Africa and it is also short for ‘Bigoted’, showing that the documents were created in isolation.
For more details about the sale, contact JP Humbert Auctioneers Ltd on 01327 359595, or www.jphumbert.co.uk