Image copyright Artists' Estate Image caption Elwin Hawthorne, Phyllis Bray, John Cooper, Brynhild Parker: Four members of the East London group of artists started by Cooper, an inspirational teacher

Two exhibitions open this month devoted to a group of working class artists from the East End of London who became art world celebrities in the late 1920s and 1930s - only to be forgotten after World War Two.

They were known as the East London Group, and among their ranks were humble office clerks, a navvy, a window cleaner, a shop assistant, a printer, a basket-weaver and an errand boy.

Now they're being rediscovered, with one exhibition devoted to their work in Southampton, and another, curated by the children's author Michael Rosen and radio producer Emma-Louise Williams, on their home turf of Bow in East London.

Image copyright Artist's Estate Image caption Elwin Hawthorne was able to depict the North Foreland Lighthouse for Shell once he and the Steggle brothers began to travel around the country

Though they had no formal art school training, the paintings they produced were highly sophisticated.

Encouraged by an inspirational teacher, John Cooper, at evening classes in Mile End and Bow, they painted what they saw around them in London's industrial, poverty-stricken East End, finding the extraordinary in the everyday.

For the most part, their subjects were smog-shrouded scenes of canals, railway bridges, terraced houses and scrubby back gardens.

There's no traffic in their pictures, and very few people, giving them an eerie, slightly surreal quality.

And their paintings are a valuable record of a world long since vanished thanks to the wartime Blitz and post-war redevelopment.

Image copyright Artist's Estate Image caption Harold Steggles with the car bought thanks to the brothers' success

Image copyright Artist's Estate Image caption Harold Steggles (left) worked as a solicitor's clerk, his brother Walter worked for a shipping firm

For eight years in the 1930s they staged an annual exhibition at one of London's most prestigious commercial art galleries, Alex Reid & Lefevre in Mayfair. Wealthy art collectors bought the group's paintings and critics raved about them.

David Buckman, who has written a book about the group, says they received enormous press coverage in leading newspapers like The Times and the Daily Mail.

"They were well received, and received as equals," he says, pointing out that two of the group were invited to exhibit paintings at the 1936 Venice Biennale alongside many of Britain's leading artists.

The Southampton show has been curated by Alan Waltham, whose interest in the group was sparked because two of its members were his wife's uncles.

Image copyright Artist's Estate Image caption Hawthorne's Demolition of Bow Brewery immortalises a world now disappeared

Image copyright Brighton and Hove Museums Image caption Cecil Osborne's Sunday Morning

Harold Steggles worked as a solicitor's clerk; his brother Walter worked for a shipping firm. Each day they commuted into the City from Romford and later Chadwell Heath, returned to have their tea and then, three evenings a week, travelled back into the East End for Cooper's classes.

Image copyright Artist's Estate Image caption Albert Turpin had multiple jobs from fireman to mayor but sketched whenever he could

Their sister Dilly, Waltham's mother-in-law and now aged a frail 100, remembers they had a "studio" - one room in the family home - and sometimes let their little sister watch them at work.

Had she wanted to paint too? I asked her. "Me? No! I couldn't paint a daffodil!" she says.

The brothers' success meant they were able to buy a car (a Ford built at nearby Dagenham) and with their friend Elwin Hawthorne and his wife Lilian, who were fellow members of the group, they broadened their range by travelling round the country to paint.

Image copyright Artist's Estate Image caption Grove Hall Park, Bow by Harold Steggles

All three men contributed images to Shell's famous series of posters depicting English scenes - Cookham in Berkshire in Walter's case, Bungay in Suffolk in Harold's, while Hawthorne's picture was of North Foreland lighthouse in Kent.

Another leading member of the group was Albert Turpin, window cleaner, wartime fireman and war artist, firebrand socialist, Labour councillor and post-war Mayor of Bethnal Green.

His work is at the centre of the second exhibition at Bow's Nunnery Gallery.

Michael Rosen says the group's work is fascinating because of their insistence on painting what they saw in unfashionable places.

"Why paint shabbiness? It's perverse. But that's what makes their work interesting and really rather wonderful."

Image copyright Artist's Estate Image caption Walter Steggles's painting of Canvey Island

Turpin's daughter, Joan Barker, who was adopted by Turpin and his wife Sally aged two at the end of the war, recalls a man who was forever sketching: his family, his fellow councillors and the streets around him. After the war he made a point of sketching buildings due for demolition, and their replacements as they went up.

Barker has her father's pre-war scrapbook, full of newspaper clippings about Councillor "Dick" Turpin and his run-ins with the law as he fought Oswald Mosley's fascist agitators. And she has his post-war sketchbooks and several of his paintings.

Image copyright Artist's Estate Image caption Elwin Hawthorne's Cumberland Market: Once a major hay market, it became an attractive area for artists

But sadly much of his work has vanished. After her father's death in 1964, her mother decided to clear out the shed at the family's Bethnal Green flat. Most of her father's paintings from the 1920s, 30s and 40s were burnt.

But it's not just Turpin's work that has disappeared. Waltham, who runs a Twitter feed devoted to promoting the group, says more than 700 East London Group paintings were exhibited in the 1930s. He has been able positively to locate just 113 of them.

Some may have been destroyed. But many others may be hanging unrecognised on walls or sitting in attics up and down the country, still waiting to be rediscovered.

From Mile End to Mayfair at Southampton City Art Gallery runs until January. The Working Artist at the Nunnery Gallery in Bow, East London opens on 29 September.