Mabel Lear, he eldest of three daughters, of Richard Lear (1834–1894), was born at Plumstead on 19th May 1871. Her father was clerk of works in the Royal Engineers Department.
The family moved to Lichfield and on 25th February 1895 she married James Quarton Braidwood, a gas engineer. As her biographer, Elizabeth Crawford, has pointed out: "Nothing can be traced of the fate of this marriage; it was presumably ended, possibly in South Africa, by the death of her husband. In 1901 she married, probably in South Africa, George Moxley Tuke, a captain in the South African constabulary." After her husband's early death she returned in 1905 to England. On the boat from South Africa she met Emmeline Pethick-Lawrence, who told her about the Women's Social and Political Union (WSPU).
Mabel Tuke joined the WSPU and in 1906 she became the organisation's honorary secretary based at Clement's Inn. She was especially close to Christabel Pankhurst and Emmeline Pankhurst. As Elizabeth Crawford pointed out: "She was affectionately known as Pansy, a nickname obviously inspired by her luminous dark eyes. Beautiful, soft, and appealing, she represented the womanly image that the Pankhursts were keen to promote in order to counteract the popular conception of the suffragettes."
On 1st March 1912 she was arrested for breaking a window in 10 Downing Street. She was found guilty and received a three weeks sentence in Holloway Prison. While she was in prison she was charged with conspiracy. However, these charges were dropped.
According to Elizabeth Crawford, the author of The Suffragette Movement (1999): In 1925 Mabel Tuke took part with Emmeline and Christabel Pankhurst, in the ill-fated scheme to run a tea-shop at Jules-les-Pins on the French Riviera. Mrs Tuke provided most of the capital and did the baking." The venture was unsuccessful and they returned to England in the spring of 1926.
Mabel Tuke died of cerebral thrombosis in Ashbrooke Nursing Home, 12 St John's Road, Nevilles Cross, Durham, on 22 November 1962.