World reknowned expert on Suffolk painter Thomas Gainsborough has branded an extract on a new biography of the artist as “absolute rubbish”.

Hugh Belsey, who lives in Bury St Edmunds, has hit out at details in the book written by James Hamilton, concerning salacious and rude elements of an unfinished landscape painting featuring a Mr and Mrs Andrews.

The author says he believed the painting of the couple, owned by the National Gallery, should be immediately reappraised, admitting the true nature of the work was so scandalous they may need to be careful in their wording.

His new book details his re-examination of the famous painting, recasting it not as a celebration of the union of two landed families, but a bawdy mockery of the Mr and Mrs Andrews he had fallen out with.

He maintains that the Sudbury-born artist was sending up his subjects with a series of rude symbols while hell-bent on revenge.

But Mr Belsey, who aided Mr Hamilton with the publication, said: “I do not subscribe to any of his theories. I do not think that it’s anything to do with the truth and is just to try and sell the book.”

Among the hidden signs Mr Hamilton claims to have identified are two donkeys trapped in a pen, a “phallic” bag tied to Mr Andrews hip complete with “floppy leather glove” and a doodle of a male’s private parts in Mrs Andrews’ lap.

The painting, completed by Gainsborough in Suffolk in 1748, is known to star Robert Andrews and Frances Carter, subjects of a carefully-arranged marriage to unite two large estates in Sudbury.

Both families were well known to Gainsborough, with a one-time friendship between the artist and Mr Andrews.

Mr Belsey said: “I do not think that it’s that much of a story in fact what is in Mrs Andrews’ hands is unfinished and appears to be a dead pheasant or partridge.

“What the painting does show is two halves of the estate being united and what Mr Hamilton is trying to convey is absolute rubbish and it’s all about trying to sell the book and it should be about trying to get to the truth.

“I helped him with the book and I think he found it useful but this element was not one of my ideas.”

Mr Hamilton added: “Gainsborough was a randy gentleman living in a randy age,” he said. “Sexual innuendo and graffiti were not foreign to him.

“It was never given a title, it was never engraved, and was put away out of the public gaze until the 20th century when all involved were long dead and whatever controversy there was forgotten.”

The painting was eventually bought by the National Gallery in the 1960s. The gallery currently describes Mr and Mrs Andrews as “the masterpiece of Gainsborough’s early years”.