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LONDON - An octogenarian woman and her son were sentenced for one of the largest, longest lasting and most diverse art scams ever in Britain, forging paintings, sculptures, carvings and statues.

Olive Greenhalgh, 82, her husband George, 84 and son Shaun, 46, had all pleaded guilty to making the forgeries, selling them as originals and laundering the proceeds.

The three, with the aged mother and father in wheelchairs, appeared in court in the northern English town of Bolton for sentencing.

Shaun Greenhalgh was sentenced to four years and eight months in jail while his mother got 12 months suspended for two years. Sentencing of her husband was delayed for a medical report.

"This family has been operating for nearly 20 years, producing and introducing a diverse range of art works," said Vernon Rapley, head of the police's art and antiques unit.

"Despite their talent and ability to reproduce these artworks and the false provenances that accompanied them, they were still living a relatively frugal life," he added.

Police said the family's scam began to come unglued in February 2006 when the British Museum became suspicious of the authenticity of three stone reliefs being offered to it by the Greenhalgh family for A3;500,000 ($1.36 million).

The museum alerted the police who began to investigate and found that the family had previously sold an Egyptian statue known as the Amarna Princess to the Bolton museum for more than A3;400,000. This too was found to be fake.

Police searched the home address of the Greenhalgh family the following month and found vast quantities of materials including an 1892 catalogue and other documentation used as source material for various articles.

Stone, silver, glass and research books were also discovered along with tools used to make the fakes.

When initially arrested the three said that all the items they had sold had been inherited.

But further inquiries showed that members of the family had been selling statues, paintings and antiques to galleries, museums and at auction for at least 17 years.

"Whilst numerous forged items have been recovered and every effort has been made to trace all the Greenhalgh forgeries there can be little doubt that there are a number of forgeries still circulating within the art market," said Rapley.

These have included paintings by LS Lowry, Thomas Moran and Samuel Peploe and sculptures and statues by Hepworth, Brancusi, Greenough, Man Ray, Henry Moore and Otto Dix.

There was also a Gauguin vase and numerous antiquities including the Amarna Princess, Assyrian stone reliefs and gold and silver items purportedly from Roman and Anglo Saxon times and various other eras and cultures.