The British Museum has called in Interpol after an art thief stole a 2,500-year-old Greek statue from the British Museum, reported to be worth up to £25,000.

The thief took the 12cm-high marble head and left with it undetected, reported the museum, prompting a review of security at the cash-strapped institution.

Sadly all museums are vulnerable to theft

Neil MacGregor, British Museum director

The theft came to light on the same day Neil MacGregor, the former head of the National Gallery, took up his new position as director.

Busy

The museum said that the Greek Archaic Gallery, where the theft took place, had been open to the public but there was no permanent guard on duty.

It said the theft was not immediately noticed and it could only be established that it was stolen from the gallery some time on Tuesday, when the museum was busy with holiday visitors.

Art dealers have been urged to be on the look out

Curators and art dealers across the world have been alerted to look out for the head which has a distinctive damaged nose and face.

Interpol, the international police organisation, are often involved in the recovery of stolen arts pieces and have been contacted about the theft.

'Risk'

It was acquired by the museum in 1922 and experts believe it could be worth up to £25,000.

Mr MacGregor said: "Sadly all museums are vulnerable to theft and small-scale sculptures are always particularly at risk.

"It is the first duty of an incoming director to review every aspect of security and I shall be doing so energetically."

The theft will highlight the issue of security and funding at the museum, which has seen contributions from the UK Government decline 30% in the last 10 years.

Up to 28 of the museum's 100 galleries are regularly closed to visitors because of a lack of staff.