LORD Nelson’s fighting sword is to go under the hammer at auction for £50,000.

The historic weapon will be up for sale at the Chelsea Antiques Fair and is being sold by maritime antique dealer Charles Wallrock of Wicks Antiques in Lymington.

While researching the 24-inch blade he found an account of its history written by Horatio, third Earl Nelson.

In it, he states that his famous ancestor, who died a heroic death in 1805, was gifted the sword by Cardinal Henry York, who said his brother Bonnie Prince Charlie had used it all his life.

And while the claim cannot be corroborated and the story is on the face of it incompatible with the known dates, it remains a curious account without explanation.

What is certain is that Nelson gave the sword to his relative William Maurice Suckling, whose family still possessed it when the third Earl wrote his account.

It then passed down the family and was ultimately bought by Charles Wallrock who said: “There is no doubt that this was Nelson’s sword – he may well have used it in action against the French.

“The curved steel blade is just short of 24 inches and dates from the 17th century. It is mounted into a later silver hilt, hallmarked ‘Nixon’, London 1752.

“That the fairly ordinary blade was remounted in silver by Nixon certainly suggests it was deemed important.

“It retains its leather scabbard and has now been mounted in a display cabinet befitting its importance.

“It is hugely desirable and the Chelsea Antiques Fair is the perfect place to put it on display.”

The fair – now owned by the online antique selling portal 2Covet – will be held at the magnificent Chelsea Old Town Hall, from September 21 to 26.

Bonnie Prince Charlie – according to Jacobite succession – was heir to the thrones of England, Scotland and Ireland.

Also known as the Young Pretender and Young Chevalier, his efforts to take the crown failed with his defeat at Culloden in 1745. He died in Italy in 1788 aged 67.

Lord Nelson went on to achieve immortality with his victory over the combined French and Spanish fleets at Trafalgar in 1805, a battle during which he was mortally wounded.

Cardinal York, who was the last of the Stuarts to claim the crown, died in 1807 aged 82.