Born in Dilston Castle, Northumberland, his father was killed in an accident while serving as a British army gunner in India. David Sweetman was adopted by an uncle who was a local government surveyor. It was traumatic for David Sweetman when at the age of ten he discovered that he was an adopted child. He had a lonely upbringing.

From 1960 to 1965 he studied fine art on a Hatton scholarship at King's College which was part of Durham University until 1963 when it became part of the University of Newcastle upon Tyne. Also studying there was the future rock singer Brian Ferry and they formed a lasting friendship. David Sweetman was briefly a presenter for Tyne Tees Television.

He moved to London with the intention of becoming a lecturer. He answered an advertisement from the then Ministry of Overseas Development and as a result travelled to Mombasa. From 1965 to 1966 he studied for an education diploma at Makerere College, Kampala. He then taught English and art at a boys' school in Dar-es-Salaam and wrote schoolbooks for the African market, including adventure stories with titles like Skyjack Over Africa.

Every Sunday morning he wrote poetry which appeared in leading journals including Encounter, the Listener, the New Statesman, Quarto, and The Times Literary Supplement. Later his poetry was collected as Looking into the Deep End, (1981), which became a Poetry Book Society Choice.

From 1969 to 1973 he lectured in art history at Hackney Technical College and continued to write children's books. In 1970 he began freelancing for the African department of the BBC World Service. He had two further periods of teaching abroad in Madagascar and Tunisia.

In 1976 he was in a London club when he met Vatcharin 'Vatch' Bhumichtitr, who was a Thai graphic art student at the London College of Printing. They then lived together for 25 years. They opened a Thai souvenir shop in Earls Court in south-west London. Their shared interest in cooking led them to establish a Thai restaurant, also in Earls Court. In 1981 an aunt of Vatcharin Bhumichtitr's in Bangkok bought him a cheap property in Soho and the Chiang Mai restaurant was opened.

They went on to set up four more restaurants, their final one being Southeast W9 in Maida Vale, where they lived in the flat over the restaurant. Starting with The Taste Of Thailand, (1988), they produced a series of cook books published under Vatcharin Bhumichtitr's name.

A regular visitor to Thailand, Sweetman worked with Vatch on the Northern Thai Group, which raised money to add a wing to a school in the city of Chiang Mai. In 1999, after discovering the plight of children born HIV-positive and abandoned by their families, they became the guiding force behind the UK/Thailand Children's Fund, which provides care and medical treatment for more than 350 children in northern Thailand.

In that same year, Sweetman collapsed with multiple systems atrophy, but, although the disease slowed him down, he remained as industrious and mischievous as ever. Last May, we went to Thailand to observe the work of the fund. By then, he walked with a stick but, essentially, everything Sweetman had been, he still was; in Bangkok, he loved both the Wat Pho temple and the Patpong sex shows.

Sweetman died in London, of multiple system atrophy.