A landscape painting, which previously sold for £35,000 has been authenticated as an original from the brush of English Romantic painter John Constable and valued at around £2 million.

Gloucestershire businessman, Henry Reid, purchased the rendition of Willy Lott’s Cottage on the River Stour from art dealer and BBC Fake or Fortune? presenter Philip Mould in 2000. At the time, Mould was just beginning his career as a dealer.

Having purchased the painting for £10,000, Mould struggled to authenticate the work as a Constable despite a fervent belief in its originality. “I had a conviction, a dream, that it was possibly right, but art dealers can’t afford to put money into a picture and hope and wait”, he explained. Unable to convince scholars he consulted in the 1990s, Mould was forced to sell the painting on.

On Sunday’s episode of Fake or Fortune? Mould was forced to confront a grim reality. Following extensive investigation and using cutting edge forensic technology the painting was finally authenticated as an early version of Constable’s Hay Wain dating to around 1820. The Hay Wain was completed in 1821.

Mould and co-presenter Fiona Bruce established a provenance for the work beginning with Constable’s son and involving a socialite who lived in London’s Savoy Hotel and a whisky baron from Scotland. “Art history has moved on so magnificently – and technology – in the last 17 years. We can do things and find things out that were not possible when I was a youngster” Mould told the BBC.

Confronted with the truth after 17 years Mould gallantly congratulated the £2 million painting’s owner and took comfort in the vindication afforded by the art investigation. “I’m thrilled for Henry”, he insisted. “I’m really happy to know that I was not deluded”.

Constable’s Hay Wain was narrowly defeated by Banksy’s Balloon Girl for the top spot in a poll of the UK’s favourite artworks in July this year.