Picasso: One of the most influential artists of the 20th century

The paintings' provenance had always been slightly questionable. They were acquired by the state after undercover detectives posing as buyers infiltrated an art smuggling ring.

The Turkish authorities concluded that the pictures had been looted from Kuwaiti royal palaces during Iraq's invasion of Kuwait in 1990.

The paintings, so the story went, had been folded in four and smuggled out of the country tucked under shirts and jumpers - a theory that went some way to explain the vertical and horizontal fold lines across the middle of each picture.

Investigation

But the Kuwaiti royal family consistently denied that they were missing any Picassos, which prompted the Turkish Culture Ministry to launch an investigation into their authenticity.

Photographs of the paintings sent to the Paris-based Picasso Administration run by the artist's son proved conclusively that they were fakes.

The culture ministry is still waiting for the results of tests on four more pictures also thought to have been painted by Picasso.

Meanwhile, the director of Russia's Hermitage Museum, Mikhail Petrovsky, condemned the paintings as being "not just copies, but very bad copies", adding that the original Picassos were kept at the Hermitage, where they had always been.

The origin of the fake pictures is still not known.