A METAL detectorist has discovered an “extremely rare” gold coin dating from the brief reign of Edward V, which is expected to fetch up to £15,000 at auction.

When heating engineer Brian Biddle found The Angel coin in a field at Tolpuddle, he initially thought it was a bottle top.

The 64-year-old quickly realised that he had come across a gold coin and shared the discovery with fellow members of the Stour Valley Search and Recovery Club.

He registered the find at Dorset County Museum and subsequent research into the coin – which features an image of the Archangel Saint Michael slaying a dragon – has revealed it was minted during the reign of 12-year-old Edward V who reigned for just 86 days in 1483.

Edward, one of only four English monarchs never to have been crowned, and his younger brother Richard, Duke of York, then vanished into a dungeon in the Tower of London.

It has always been widely believed that they were murdered on the orders of their uncle, who then succeeded Edward as Richard III.

The coin will be auctioned by Dix Noonan Webb in London on Wednesday, March 15.

Bournemouth-based Mr Biddle, who has only been a detectorist for 18 months, said: “I was fortunate to find this. “It was about four or five inches down and at first I thought it was a bottle top as we find a lot of things like that.

“Once I got it out of the ground I realised it was a gold coin.”

Peter Preston-Morley, a coins expert at Dix Noonan Webb, said: “This coin is important partly because it is extremely rare but also because it is a link to one of the greatest mysteries in English history.

“The story of the ‘little princes in the tower’, as they have become known, still fascinates us more than 500 years later and arguments over whether or not Richard was responsible for their deaths are still going on.”

Richard, Duke of Gloucester, ordered the boys’ imprisonment and then seized the throne as Richard III on June 26, 1483. Shortly after that the dies used to mint coins were altered to read RICARD DI GRA and the mint mark was overstruck with Richard’s personal emblem, a boar’s head.

The boys’ exact fate is unknown but the most popular theory is that they were smothered with their pillows on the orders of their uncle, and this forms the basis of William Shakespeare’s play Richard III.

The Angel found in Tolpuddle miraculously survived repeated ploughing by farmers down the centuries to emerge in good condition 533 years after it was minted.

“It’s the best thing that I have ever found,” Mr Biddle added.

He will split the proceeds of the sale equally with the farmer on whose land it was discovered.