A NEW exhibition of long lost masterpieces that would have been worth a total of £20 million - if they weren't all fakes.

The Metropolitan police held the three-day exhibition for art experts hidden away in a room in London's Victoria & Albert museum.

Dozens of forged and faked artwork from past and present criminal cases went on display, which the Met's Arts and Antiques Unit say is just the tip of the iceberg in London - the world's second largest art market.

Detective sergeant Vernon Rapley, the head of the unit, said fakes were being unknowingly sold through auction houses and dealers to eager treasure hunters and collectors for thousands of pounds.

Some gangs have become so skilled they can now fake ancient 4th Century Roman silverware, stone tablets, oil paintings and water colours.

Works by lesser known artists, valued between £10,000 and £20,000 - rather than Rembrandt or Van Gough - tended to be faked so as to not to arouse too much suspicion in the art world.

Mr Rapley said his advice to experts and collectors was to be more skeptical of claims when missing artwork suddenly appears.

He said it was becoming so prolific that it was undermining the history of art as the faked pieces often became included official archives.

"Collectors are going to be very excited about finding something that they've possibly been looking for their whole career," he said.

"Sometimes they do not even have to be very good because it the provenance, the history of it, that sells the art."

The V&A show includes fakes by Staffordshire artist Robert Thwaites, who was jailed for two years in September.

Thwaites earned thousands by expertly faking paintings that he claimed were by the Victorian painter John Anster Fitzgerald.

He was only caught after tests discovered a white pigment in a painting - which sold for £110,000 in an auction house - that did not become available until 10 years after it was supposedly finished.

Ironically, police say Thwaites can look forward to a lucrative career as a legitimate artist when he is released.

Notorious forgers, such as John Myatt, who was jailed in 1998, are often in demand to make made-to-order "genuine" fakes.

It's not known how much the faked and forged artwork industry is worth in London.

But police say such crimes were becoming more prolific and were being used as currency to fund terrorism, gun running and drug dealing.