'Queen's knickers' for sale on eBay

The undergarment, which has already attracted bids of more than £3,000, is embroidered with the letter E – presumably for “Elizabeth” – and a picture of a crown.

They are purportedly being sold by the estate of Baron Joseph "Sepy" de Bicske Dobronyi, described as an aristocrat, art collector, traveller and Playboy.

It is alleged the bloomer-style knickers, which have not been confirmed as authentic by any official sources, were left on a private aeroplane during the Queen’s visit to Chile in 1968.

There, it is claimed, they were picked up by the pilot and given to his friend, Hungarian-born Dobronyi.

After the latter died in 2010, it is said his family discovered the garment and are now auctioning it on internet site eBay.

The knickers, listed as an “item that has been previously used”, are advertised as being in good condition, despite some yellowing with age.

They have four small pearl-like button and a monogram of the Royal crown, along with two flowers on a stem with leaves, and are hemmed with crocheted lace.

The undergarment, which has a 26 inch waist and is 16 inches long, is advertised on the website as a “once in a lifetime opportunity to acquire and own a piece of collectable Royal memorabilia.”

The listing, which implores shoppers to use the opportunity to celebrate the Queen’s Jubilee, also notes: “Since Buckingham Palace or the garment maker have not confirm or deny the authenticity that this pair of underpants are from Her Majesty, Queen Elizabeth II, the estate cannot confirm its provenance and it is the buyer’s responsibility to do that on their own before bidding.”

Somewhat hopefully, it proclaims: “In either case this is an excellent example of a vintage undergarment of that era and very collectable.”

Dobronyi, who lived in America, was a jeweller, sculptor and artist, and has been called “the Hugh Hefner of Miami”.

Last year, a pair of knickers owned by Queen Victoria fetch £9,375 at a British auction house.