Born in London in 1916, Margaret Thomas studied at Sidcup Art School and then won a scholarship to the Slade School of Art but left for the Royal Academy after two years, where she studied under Thomas Monnington and Ernest Jackson.

She is a member of the New English Art Club and the Royal Society of British Artists. She is a regular exhibitor at the Royal Academy and the Royal Scottish Academy. In 1981 she won the Hunting Group Award for oil painting of the year.

Margaret Thomas has had several solo shows. The Leicester Galleries London, in 1949 and 1951, Aitken Dotts and the Scottish Gallery in Edinburgh on numerous occasions, the Mall Galleries London, the Maltings Concert Hall Gallery, Snape in 1982 and three shows at Sally Hunter Fine Art, London, the last in 1995.

'Her work is included in many notable Public and Corporate Collections such as the Chantrey Bequest, Arts Council, Exeter College Oxford, Bath University, Warburg and Co, Lloyds of London and HRH Prince Philip. Bernard Dunstan RA, writing in the introduction to the catalogue of her 1995 exhibition at the Sally Hunter Gallery comments:

' It is probably in the still life with flowers, an inexhaustible subject for her that Margaret Thomas is best known....she sometimes finds unexpected beauty at the point when most people would consign the flowers to the dustbin; a faded or drooping plant can have its own sad charm. She is able to paint, with apparently casual directness, pictures that are strongly and visually designed, partly because she is lucky enough to have been trained at a time before art schools gave up drawing.