Millionaire's death could see Constable masterpieces back in the UK

Sir Edwin Manton, who grew up just a few miles from the Stour Valley immortalised by Constable, was one of the most generous patrons of the arts Britain has ever seen, donating millions to the Tate Gallery in London.

But following his death aged 96 last Saturday, attention is being turned to what will become of his 1997 promise to bequeath a further £5m to the Tate as well as the future of his 50-strong collection by the English landscape painter. He also possessed "a number" of works by Turner including at least one oil painting, and a sketch of Plymouth. There is speculation that the collection could end up at the Tate, where it would be an invaluable insight into the development of the artist.

Among the sketches, watercolours and oils that make up the Constable collection are a number of minor masterpieces, most on paper. There are preparatory drawings of Salisbury Cathedral and a small oil painting,Woodland Scene Overlooking Dedham Vale (1802-3). The scene helped pave the way for one of Constable's most famous works, Dedham Vale Morning (1811).

Also in his collection was Glebe Farm, a previously undiscovered oil sketch, which has hung in Tate Britain since 1997 but which will pass to the gallery on his death. Sir Edwin's will has not yet been published but, during his life, he had planned to make over his collection to a charitable foundation that would loan works to public collections. He was in discussions with his lawyers right up to his death and continued to collect paintings, despite competition from Lord Thompson and Paul Mellon. In his own words, his bequests would allow his grandchildren to "see what grandpa spent his money on".

Martin Bailey, of The Art Newspaper, said speculation was beginning to mount over what happens next. "It would be good if they could be kept together in a public collection," he said. "There will be a great deal of interest in what will happen."

Sir Edwin made his fortune in the American insurance market. Born in Earls Colne, Essex, just a few miles from Constable country, he arrived in New York in 1933. By the time of his death he was reported to be worth £260m. He was virtually unheard of in Britain until 1997 when he received a knighthood after donating £12m to the Tate. As well as helping raise £3m to save Constable's Waterloo Bridge, he also gave the gallery £7m towards a new building. He helped establish a fund to buy art from North and South America for the Tate.

Self-effacing and fiercely patriotic, despite his 70-year sojourn in the US, he explained that he had always sought anonymity "to protect myself from people importuning me". When his identity became public, he said of his collection: "It's better than spending your money on bottles of Scotch." So extensive were his holdings in the artist it is said he failed to notice when seven works were stolen from his home.

It is thought that his collection has only been shown once publicly, at the exclusive Salmagundi Club in Manhattan in 2000. Other works included Constable's Flailing Turnip-Heads -- East Bergholt (1812-15) and two Cloud Studies from 1821-22.

The Tate director, Sir Nicholas Serota, paid tribute to Sir Edwin. "He continued to play an active role in the affairs of Tate well into his nineties," he said. "His passion and commitment will be hugely missed by all at Tate."

Tate Britain is staging a Constable exhibition next year, showcasing his large oil paintings.