A builder who bought a marble statue from a reclamation yard for £300 is set to sell it for £100,000 after it was revealed to be the work of an Italian master sculptor.

The 290-year-old Italian marble maquette of Pope Clement XII Corsini was discovered by the eagle-eyed bargain hunter at a salvage yard in Wiltshire.

It had come from a country house near Andover in Hampshire and the yard owners thought the weathered sculpture was made of concrete.

But the savvy collector thought there might be something special about it and his gamble is now set to pay off.

The 26in figure was created by Italian Baroque master Pietro Bracci, who is best known for carving the central figure of Rome’s iconic Trevi Fountain.

He made the Pope maquette in preparation for a large bronze statue that once graced the Great Hall of the Palazzo Nuovo on the Capitoline in Rome.

The original statue no longer exists and this is believed to be the only surviving maquette, making it both rare and important.

The anonymous vendor has put it up for auction with Salisbury-based Woolley & Wallis.

The 290-year-old Italian marble maquette of Pope Clement XII Corsini was discovered by an eagle-eyed bargain hunter at a salvage yard in Wiltshire

The 26in figure was created by Italian Baroque master Pietro Bracci, who is best known for carving the central figure of Rome’s iconic Trevi Fountain

They have given the sculpture a pre-sale estimate of £10,000 but it could sell for ten times that as there has already been considerable international interest in it.

Mark Yuan Richards, Woolley & Wallis furniture specialist, said: ‘This is an exceptionally exciting discovery.

‘To have a rare eighteenth-century marble figure of Pope Clement XII by Pietro Bracci come to light, and now be offered for sale, is a remarkable opportunity.

‘Bracci was one of the great sculptors of eighteenth-century Rome, and this extraordinary survivor offers a tangible connection to the world of the papal court and the artistic splendour of the period.

‘The vendor is not a professional antiques dealer but he has got an eye for it.

‘He found it at a reclamation yard in the last couple of months. They thought it was concrete so he bought it for £300 then realised it was marble.

‘He had a feeling it was good, but he didn’t know it was signed or how important it was.

‘It is in quite weathered condition, it’s been in a garden outside for maybe 50 years so it’s not in perfect condition but it’s pretty much unique.

‘The original bronze was melted down and the only known representation before this was an engraving of it.

‘How it ended up in a garden in Hampshire we don’t know. It might have been gifted to a Brit on a Grand Tour in the 18th century or a diplomatic gift for someone who knew the pope.

‘We’ve had international interest already and it’s still early days. It’s hard to predict because Bracci works don’t come onto the market hardly ever.’

Bracci was a key creative figure in 18th century Rome and had a distinguished career, also making portraits and tombs for Popes Benedict XIII and XIV.

He was commissioned in 1736 to make the bronze, funded by the Roman Senate, to commemorate the pope’s donation to the Capitoline Museums.

Pope Clement XII restored papal finances and spearheaded a remarkable programme of artistic, architectural, and civic renewal during the decade that he governed, from 1730-1740, including the initiation of the Trevi Fountain.

The pope’s bronze statue did not stay at the Palazzo Nuovo long. It was subsequently moved and melted down during the First Republic in 1798.

Until the discovery of this marble maquette, the only known representation of the former bronze was an engraving by Stefano and Rocco Pozzi.

The sculpture will be sold on October 8.