John Fairbairn, who has died aged 86, was a long-serving chairman of the Esmée Fairbairn Foundation, one of the UK’s largest grant-giving charities, and deputy chairman of the pioneering unit trust group M & G. Both those organisations were the creation of John Fairbairn’s great-uncle Ian (1896-1968), who was an ardent believer that equity investment should be available to all – and the founder in 1931 of the first British unit trust, modelled on American mutual funds and launched by Municipal & General Securities. Thirty years later he endowed the bulk of his shareholding in M & G into a charitable trust – both to secure M & G itself against takeover and to commemorate his wife Esmée, who had been killed in an air raid during the war. John Fairbairn served as a trustee of the Esmée Fairbairn Foundation for 42 years, and as its chairman from 1988 to 2003. In that role he was a thoughtful and committed helmsman of its developing focus on the arts, young people, the environment and social change – to which it now gives more than £40 million per year. John Sydney Fairbairn was born at Steventon in Hampshire on January 15 1934 into a family of sportsmen. His Australian-born grandfather Steve Fairbairn was a celebrated oarsman, as was his uncle Ian, who rowed for Great Britain in the 1924 Olympics. John’s father Sydney Fairbairn played first-class cricket, won an MC in France in the First World War and was briefly married to the heiress and writer Nancy Cunard before marrying Angela Fane, with whom he had two daughters and a son, John. A happy Hampshire childhood was disrupted by Sydney’s death, aged 50, when John was nine; thereafter he was taken under the wing of two uncles, his mother’s brother Jack, and Ian Fairbairn – the latter introducing him to chamois hunting in the Pyrenees, among other pursuits. John was educated at Eton and did National Service as a second lieutenant and tank commander in the 17/21 Lancers in Germany before going to Trinity College, Cambridge, to read Classics. He travelled the world and qualified as a chartered accountant before joining M & G in 1961. During his tenure the firm emerged as the acknowledged leader of its sector, managing unit trusts for half a million savers, and an influential force in City deal making. John Fairbairn was its deputy chairman from 1979 to 1989 and a non-executive director until 1999, when M & G was taken over by Prudential and the Esmée Fairbairn Foundation sold its remaining shares. He also exercised a voice in policy issues as chairman of the Unit Trust Association and deputy chairman of Lautro, the regulatory body for the sector. He was a trustee of the Dulwich Picture Gallery, the Royal Pavilion at Brighton and the Monteverdi Trust, a council member of King’s College London and Buckingham University, and a deputy lieutenant of West Sussex. Tall, stylish and gregarious, with a famously loud laugh, John Fairbairn delighted in making friends of all ages. He loved opera at Glyndebourne, read widely and had an eye for beautiful things. At his home in Sussex, and later with his second wife in Dorset, he was the devoted pater familias of an extended brood. He married first, in 1968, Camilla Fry, née Grinling, with whom he had a son and two daughters. Camilla had five children from her previous marriage, to the inventor and socialite Jeremy Fry; she died in 2000 and John married secondly, in 2001, Felicity, née Ballantyne, widow of the 3rd Lord Milford and former wife of the banker Rodney Leach (later Lord Leach of Fairford), with whom she had four children. He is survived by Felicity, his children of the first marriage, and his stepchildren.