Police called to the scene were too late to stop the thief

The trophy was stolen from a stamp exhibition in London - but was found in a hedge by a dog called Pickles.

The letter, sent to FA chairman Joe Mears before Pickles' heroics, will be sold in Chester on 18 October.

The note's author, who calls himself Jackson, threatens to melt the cup if not given £15,000 in £1 and £5 notes.

If I don't hear from you by Thursday or Friday at the latest I assume it's one for the POT

Line from ransom note

The trophy, said at the time to be worth £30,000, was stolen from the exhibition in Westminster on 20 March 1966 - four months before the tournament.

The ransom note reads: "Dear Joe Kno [sic] doubt you view with very much concern the loss of the world cup... To me it is only so much scrap gold.

"If I don't hear from you by Thursday or Friday at the latest I assume it's one for the POT."

On police advice, Mr Mears, who was also chairman of Chelsea Football Club, pretended to agree to the demand.

The trophy was found well in time to be presented to Bobby Moore

An undercover policeman met "Jackson" in Battersea Park in London, with a suitcase stuffed with newspapers, covered with a layer of £5 notes.

"Jackson" - who was really a former soldier called Edward Betchley - was still being questioned when Pickles found the trophy, seven days after the theft.

The theft led to a replica World Cup trophy being made, which was surreptitiously swapped with the real thing during the celebrations after England's victory in the final at Wembley.

The ransom note is one of a series of documents relating to the infamous theft to be auctioned by Bonhams.

Other items include various witness statements, Betchley's charge sheet, a plan of the exhibition hall and some photographs in a folder marked "Bow Street Magistrates Court", including pictures of the trophy still wrapped in newspaper, of the briefcase containing ransom money and Barclays Bank envelopes, and of Joe Mears' Ford Zodiac with the number plate CFC 11, which was used in the police operation to catch the thief.