SOTHEBY’S has withdrawn three Damien Hirst prints from an auction this month amid claims that they are fakes, The Times has learnt. Christie’s is also investigating an example offered in its forthcoming sale.

Each of the images is one of Hirst’s trademark spot prints, which feature patterns of randomly coloured circles.

The artist is being targeted by forgers, it is believed, with several fakes having come to light in recent months. The prints are worth a fraction of the prices fetched by his best-known works — notably his shark, reportedly bought two years ago for £6.5 million — as forgers focus on works less likely to be noticed.

Sources told The Times yesterday that the signatures on prints titled Valium, Opium and Lycergic Acid Diethylamide were not Hirst’s. The paper, the ink and the colours of the dots were also wrong, it is thought.

One expert said: “Suddenly, there’s a spate of very clever forgeries. The printing technique on these prints is quite complicated. They’ve been good enough to fool Sotheby’s and Christie’s.

“Hirst ought to be worried. If people can’t rely on what they think they’re buying, they’ll stop buying his work. It will kill his market.”

The market has been flooded with so many fake prints by Salvador Dali that some salerooms will not touch him any more. No one can be sure what they are buying. Sotheby’s confirmed that the three “Hirst” prints were withdrawn ten days before the Old Master, Modern & Contemporary Prints sale scheduled for October 3. After initial denials, Christie’s said that it was “currently investigating” the authenticity of one of the images in its October 25 print auction.

This summer two other fake Hirsts appeared on the market. John Brandler, a specialist in modern British paintings, bought a T-shirt with a drawing of a skull worth up to £10,000 as a genuine piece, and three rolls of wallpaper, valued at up to £500 a roll. As fakes, they are worthless.

The dealer discovered that the fake T-shirt bore exactly the same provenance, or sale history, as the original, which he had sold 18 months earlier to another dealer. When a new dealer approached him, he assumed it was a chance to buy it back and sell it to another collector. But as soon as it was delivered to his gallery, Mr Brandler noticed subtle differences and the crucial absence of Hirst’s signature on its back.

His archival photographs of the original confirmed his suspicions. He realised that the forgers had taken an image from the internet, blown it up and copied it.

The irony is that Hirst has been accused of copying other artists’ ideas and passing them off as his own. In 2003 Robert Dixon, a computer graphics artist, said that Hirst had copied one of his circular designs — which Hirst denied — and in 2000 Norman Emms, a toy designer, was shocked to find that his 25cm (10in) anatomical study had been reproduced as Hirst’s sculpture Hymn.

Neither Hirst’s office, Science, nor his dealer, the White Cube, was prepared to comment. Hirst is among several contemporary artists in whom forgers are now taking a particular interest. The Times revealed last year that Christie’s and Bonhams had to withdraw fake paintings purporting to be by Peter Howson, a leading British artist.

FAKING IT

The most infamous British forger of the 20th century was Tom Keating, who painted works “by” Samuel Palmer found on the market