Radev collection: tale of three art lovers to be told in new touring exhibition

One was a Bulgarian stowaway who became the love of an English literary giant; the second was a gentleman art dealer who once had an affair with the opium-addicted Jean Cocteau; and the third was an aristocratic music critic who inherited one of Britain's largest houses. Together they created a remarkable art collection about to be seen in public for the first time.

The Radev collection, containing works by artists including Amedeo Modigliani, Graham Sutherland and Alfred Wallis, can from this weekend be viewed online.

A week later, selected works will go on display at the Pallant House gallery in Chichester before touring to Lincoln, Bath, Falmouth and Kendal.

The collection of around 800 works is named after Bulgarian émigré Mattei Radev, who died in 2009. He was left it by Eardley Knollys in 1991 and he in turn was bequeathed it by Eddy Sackville-West in 1965.

The driving force behind the project is writer and curator Julian Machin who believes it is high time the stories were told and the work was seen.

"We are going to put them in a place where they never go away and we are going to honour Mattei's name," he said.

"It is an important collection. It is a record of three people's tastes in changing times."

The collection shines a light on a remarkable 20th century story of love, friendship and gay flings which has a supporting cast of characters that includes Cocteau, EM Forster and members of the Bloomsbury group. It is named after Mattei Radev who fled Communist Bulgaria as a stowaway on a Glasgow-bound cargo ship, arriving in London in 1950 where he held down a series of dead-end jobs.

His life changed when, while working as an orderly at Whittington hospital in north London, he had the good fortune to meet the eye surgeon and gay rights activist Patrick Trevor-Roper.

That opened doors and soon he was lodging in the grand Nash terrace house on Regent's Park of gallery owner Robert Wellington.

It was through this that Radev learned the art of picture framing and created a flourishing business.

In 1960, Radev met EM Forster and, despite the 46 years difference, they fell in love and embarked on what Machin called "a secret, somewhat tortured affair".

Machin added: "It was secret because it suited both of them for it to be secret. Mattei was a modest man."

Among the hundreds of paintings in the collection is one with an outstanding provenance.

The writer Christopher Isherwood gave Two Male Nudes by Keith Vaughan to Forster who then gave it to the man he loved - Radev. Machin said Radev was too much a minor footnote in biographies of Forster, something he is aiming to put right with a new book on Forster due out next year.

Radev was left the collection by his close friend Knollys, a passionate collector who ran the influential Storran gallery in London with his partner Frank Coombs between 1936 and 1944, staging sales of artists including Modigliani, Maurice Utrillo and Chaïm Soutine.

After Combs died during an air raid in 1944 Knollys decided to close the gallery and became a regional representative of the National Trust.

Machin said Knollys was "an absolute gentleman" with wonderful twinkling eyes. For all his strait-laced English country gent demeanour Knollys also led a more interesting life than many and was, at one stage, the lover of Jean Cocteau.

During the winter of 1928 at the Hotel Welcome in Villefranche, Knollys stayed up all night translating Cocteau's play La Voix Humaine while its author was on heroin.

Knollys had been left the collection by the third man in the story, Eddy Sackville-West, an intellectual aristocrat who inherited the title of fifth Baron Sackville as well as the huge family pile, Knole in Kent.

He was part of the tangled Bloomsbury set although somewhat overshadowed by his better known cousin Vita Sackville-West, who had a famous affair with Virginia Woolf. "Vita was very nice to his face but my God, she belittled him behind his back," said Machin.

One of Sackville-West's true loves was music and, writing for the New Statesman, he became of one of the most distinguished music critics of his generation, promoting the works of young composers such as Michael Tippett and Benjamin Britten who, in 1943, dedicated Serenade for Tenor, Horn and Strings to him. He was also one of the first to recognise and acknowledge the genius of Kafka.

Eton-educated Sackville-West met Winchester-educated Knollys at Christ Church, Oxford, in 1920 – think Brideshead Revisited – and after a fleeting love affair they became lifelong friends.

Sackville-West made many friends although his love life was trickier.

"In matters of the heart his tendency was to be masochistic and unhappy," said Machin. He did though build up a stupendous collection of pictures which has been added to by both Knollys and Radev.

It includes works by Duncan Grant, Wallis, Sutherland and Ben Nicholson. Some highlights include a striking Modigliani portrait of his friend Soutine; a Dorset landscape by Lucien Pissarro (son of Camille) given to Knollys by the artist's wife Esther Pissarro; and a 1913 bronze dancer figure by Henri Gaudier-Brzeska.

The collection currently hangs in a private house where the walls – living room, kitchen, stairway, bedrooms – are covered floor to ceiling with art.

In a video which will be on the Radev collection website, Richard Shone, editor of the Burlington Magazine, recalls seeing the collection under various roofs, describing it as "an extraordinary treasure trove of paintings".

It might be expected that a lot of works would have a kind of gay theme, but that is not the case - Knollys was quite "buttoned up", said Shone.

One clear exception is a striking portrait of the Bloomsbury set sculptor Stephen Tomlin, strong and bare chested, who had a fling with many of the people he came across including Eddy.

Not all the works have yet been catalogued but the ones which have will be on its new website, when it goes live on Saturday.