A collection of photographs by Bradford-born artist David Hockney are set to fetch around £25,000 at an auction at Sotheby's.

The ten photos will go under the hammer at the renowned London auctioneers on May 22 and Hockney enthusiasts are expected to be out in force to snap them up.

A double self-portrait, showing Hockney in front of a self-portrait of himself wearing a "Him Exclusive" t-shirt, is expected to fetch the top price.

Entitled "Self-portrait in front of self-portrait with a blue guitar", the Polaroid could go for as much as £6,000.

Another 1977 Polaroid, showing Gregory Evans sleeping in front of the same Hockney self-portrait, could fetch £5,000.

Hockney's colour portrait of an oar in a swimming pool could fetch £1,500, while a picture of a sun umbrella on a near-deserted beach is expected to sell for about £1,200.

Two portraits of Hockney by photographer and designer Sir Cecil Beaton are also included in the sale and are expected to fetch about £600.

In 1998 more than 100 Hockney photographs, assembled by airline worker Brian Baggott over 25 years because he could not afford an original painting or print, fetched £94,335 at Christie's in London.

Hockney fans who cannot make the sale can see an exhibition of his work, featuring five double watercolour portraits, at the National Portrait Gallery in London.

The exhibition runs until June 29 and admission is free.