The small picture of a crucifix came from a flat in Ealing, west London, that was owned by Polish expatriates, one of whom claims to be the illegitimate daughter of Picasso.
Mark Harris, an art historian who part-owns the 15-inch-square drawing, earlier this year advertised for a fingerprint expert on the Internet after he discovered a Picasso signature and a right-hand thumb print on the drawing.
He was put in touch with Martin Leadbetter, head of Cambridgeshire Police's fingerprint unit, who agreed to try to authenticate the drawing. Since 1991 the owners of the drawing, which is in black ink on paper, have been attempting to get a copy of Picasso's thumb print from his family and the Picasso museum in Paris, but have been refused.
Mr Leadbetter has made two trips to the Bibliotheque Nationale museum in Paris and has examined about 500 Picasso originals in search of a copy of the artist's thumb print, but has failed to discover any so far. "It will take a lot of detection to track down the thumb prints," he said.
Mr Leadbetter hopes to locate a plaster cast of Picasso's hands and a work certificate from the 1940s which is supposed to have his prints on it.
The drawing was found by a Brighton art dealer along with four other pictures, also with Picasso's name on them, during a house clearance in the 1970s. The Brighton dealer kept the pictures for several years, but sold them after experts from Sotheby's and Christie's failed to authenticate them. The crucifix picture was bought in 1991 for pounds 25 and is now owned by a syndicate of four people.
Commenting on the drawing, Mr Leadbetter said: "It's an awful thing to look at - I wouldn't pay pounds 25 for it."
Mr Harris, who lives near Worthing in Sussex, said yesterday that he uncovered a wealth of evidence that showed the drawing was by Picasso. "I and a number of Picasso historians are convinced it's an original," he said.
Mr Harris added that he believed the picture was related to Picasso's most famous work, Guernica, which made it "historically significant" and valuable. Estimates have varied from pounds 1m to pounds 20m, he said.
Mr Harris added that the Picasso estate was refusing to help authenticate the drawing despite numerous pleas.
Picasso is generally considered to have been the most influential artist of the first half of the 20th century, a superb draughtsman who developed Cubism and radically changed the nature of art.
Picassos vary hugely in price, from pounds 500 for a limited-edition etching to the pounds 18m which Sir Andrew Lloyd Webber paid for the 1903 Blue Period Portrait of Angel Fernandez de Soto at Sotheby's in New York in May 1995. Also last year, a drawing from the Zumsteg collection, Tete de Femme, sold for pounds 1.76m.
A police officer successfully used finger prints to identify lost work by the painter JMW Turner a year ago. The painting later fetched pounds 100,500 when auctioned last December.Reuse content