Forsythe collected the works over 13 years

Among the paintings are a Northern River Scene - a dramatic panorama of the city of Lincoln - which is expected to fetch between �200,00 and �300,000.

Lowry's bleak industrial landscapes of mills and stick figures are justifiably famous though for most of his life he painted only part-time while working as a debt collector and clerk.

He was a complex, solitary man but public interest in his work slowly gathered, though the critics have rarely been convinced.

'Isolation'

By the time he died in 1977 he was the most famous painter in Britain.

LS Lowry painting only part-time

The acclaimed Lowry centre in Salford is dedicated to the memory of Manchester's best-known artist, though it does much more than just exhibit Lowry works.

But his later works and portraits are considered to be kitsch and one-dimensional.

"Altogether," says Daily Telegraph art critic Martin Gayford, "I consider Lowry to be an interesting artist who doesn't quite make the major league."

"Perhaps he was a little limited by isolation."

Recent sales of LS Lowry's work have failed to reach their expected prices.

Nostalgia

Last summer two Lowry paintings - Iron Works and Manchester City vs Sheffield United, failed to fetch their reserve prices at a Sotheby's auction.

Then in December an oil on canvas painting of a Welsh colliery was withdrawn from sale having failed to reach its price of �1m.

Going to the Match sold for a record �1.9 million

"Lowry was a melancholy compulsive who painted the industrial north of England through deeply disturbed eyes, and caught aspects that nobody was prepared to look at," says art critic Jonathan Jones.

Now that the heavy industry and mining communities are vanishing, Lowry's works are seen as nostalgia rather than a bitterly realistic take on how industry deprived people of identity.

The sale of the Forsyth collection - which includes two paintings that previously belonged to entertainer Max Bygraves and a framed cloth cap belong to the artist - will take place on 8 June as part of British Art Week.

A Christie's spokeswoman said that Forsyth's collection constitute "everything you would want from a Lowry."