A John Constable painting, first believed to be a copy, could fetch up to £5m at auction after it was proven to be an original.

The oil painting first went on sale last year at an auction in Cincinnati, Ohio, with a guide price of just $1000-$2000.

After an anonymous bidder spotted that the piece may have been more than just a duplicate a bidding war meant that the work sold for $53,750 (£40,000).

East Anglian Daily Times: This version of The Glebe Farm is the fifth known to exist, with three others in the Tate gallery, and one in the Detroit Institute of Art.This version of The Glebe Farm is the fifth known to exist, with three others in the Tate gallery, and one in the Detroit Institute of Art. (Image: Sothebys)

Now proven to be legitimate, the piece is up for auction again but is fetching a pre-sale estimate of £3 to £5million pounds, at Sotheby's, London in December.

Julian Gascoigne, Sotheby's specialist of British Pictures, said: "The existence of a lost preparatory study for ‘The Glebe Farm’, one of the most personal and evocative of Constable’s great paintings, has long been known by scholars.

"Listed in the artist’s studio sale, the re-emergence of this important work after 180 years, particularly in such an exceptional state of preservation, represents one of the most significant and exciting discoveries in Constable scholarship for a generation."

East Anglian Daily Times: The auction which takes place on December 8th is expected to attract global attention.The auction which takes place on December 8th is expected to attract global attention. (Image: Courtesy of Sotheby's)

The image was based on a sketch of the home of Constables close friend Dr Fisher, bishop of Salisbury, and following his death in 1825 the artist decided to return to the image and produce several oil-painting versions.

The Tate Modern Gallery is home to three of the five versions of The Glebe Farm, with the other housed in the Detroit Institute of Art.

Speaking around how often a painting goes through a journey like the one that this has, Mr Gascoigne said it happened from "time to time", however it was "very rare for something as significant as this to go unnoticed".

The work will go on sale as part of the Old Masters auction on December 8, and is expected to attract interest from all over the globe.

Bidders are expected from the far East, Russia and Australasia.

Sotheby's specialist of British Pictures Julian admitted "it is very hard to predict where something like this could end up".