Teri Horton bought the paint-splattered canvas at a California junk shop for a joke. But the joke may be on the art world instead.

The retired lorry driver paid $5 for the drip painting in 1991, bartering the price down from $7. Now a fingerprint on the painting has raised the possibility that it is in fact a masterpiece by Jackson Pollock, the world’s priciest artist.

If it is accepted as authentic, the picture would be worth $40 million to $50 million (up to £26.2 million). Last month Pollock, who died in a car crash in 1956 aged 44, was reported to have set a world record price of $140 million for No 5, 1948.

Ms Horton, 74, of Newport Beach, California, had never heard of Pollock. Indeed, when told that the painting might be by the abstract expressionist, she asked: “Who the f*** is Jackson Pollock?” — now the title of a documentary about her ensuing 15-year struggle with the art world.

Ms Horton bought the 48in by 65in (120cm by 165cm) picture in San Bernardino. She took it to a friend’s trailer home, where they laughed at it. “We were going to throw darts at it, but we sat there and drank beer and never did get around to it,” she told the Toronto Star.

Ms Horton then put it in storage. The first indication that she might have something special came when, to clear out her clutter, she offered it for sale to friends. An art professor at a nearby university told her that he thought she might have a Pollock, beginning a long quest to authenticate the work.

The International Foundation for Art Research rejects the idea that the painting is a Pollock. Thomas Hoving, a former director of the Metropolitan Museum, New York, who investigated the claim for the documentary, said: “I think somebody had a house in some sunny part of the world, Palm Beach or something, and wanted an abstract painting, maybe like a Pollock, in colours that would have fit the room.”

But Peter Paul Biro, an art restorer, says that he has matched a fingerprint on the painting to one on a paint can from Pollock’s studio in East Hampton, New York. “Since Pollock was known to work alone and had no assistants or pupils the probability of the fingerprint on the blue paint can being Pollock’s is very high,” he writes on www.birofineartrestoration.com/Pollock/Pollock.htm.

He then sought to match the fingerprint on the painting to a Pollock work of undisputed provenance. In September he discovered what he says is a second matching print on Naked Man with Knife, at Tate Modern, London.

“The new data now firmly identifies Jackson Pollock as the contributor of the fingerprint on the blue paint can, as well as on the Horton submission,” he said.

FINDERS’ COUPS

Another guest on the Antiques Roadshow took in a vase that had been retrieved from a friend’s garage and then used for holding potted plants. The vase was identified as a 16th-century Ming wine holder and was valued at £10,000