A MARBLE statue once used as a garden ornament at a Georgian country house has surpassed all expectations by selling at auction for £12.2m.

It is understood the second century Roman Imperial sculpture of Leda and the Swan, which is 4ft 5in, was moved indoors – to the corner of a room at Aske Hall, near Richmond, North Yorkshire, before finally being recognised as an ancient treasure.

It had been expected to fetch between £1.2m and £1.9m at Sotheby’s antiquities sale in New York on Friday, but four determined bidders pushed it to ten times its estimate, before an anonymous buyer clinched the statue over the phone.

The Marquess of Zetland and the rest of his family had believed the artwork was created in modern times and their staff regarded it as “part of the furniture”.

Until its rediscovery, despite having been kept at the estate by the Dundas family since 1788, the statue had remained entirely unknown to scholars.

It does not appear in any of the major surveys of ancient marble sculpture in English country houses, but is mentioned in Robinson’s Guide to Richmond of 1833.

The piece was spotted by antiquities specialist Dr Florent Heintz during a routine visit to the hall, which has an impressive collection of historic furniture, paintings and porcelain.

Dr Heintz found the sculpture had a rich provenance, being one of four antiquities bought in Rome during the 18th Century by the 1st Earl of Zetland on behalf of his father.

The most prized of the antiquities – a statue of the Lysippean Eros – was stolen from the grounds of Aske Hall in the Seventies and has never been recovered.

The sculpture was offered for auction by the will trust of the 3rd Marquess of Zetland, Lawrence Dundas, who was chairman of Catterick and Redcar racecourses and died in 1989.