Fiercely driven, passionately idealistic and secretly tormented, the British clergyman Michael Scott was a key figure in the struggles against apartheid, colonialism and, later, nuclear weapons. His activities during his ministry in South Africa in the late 1940s and early 1950s led to his being imprisoned and banned by the apartheid regime, whose attempts to absorb the territory of South West Africa (now Namibia) he was instrumental in frustrating. His fervent – some would say quixotic – campaigning fervour also led to his deportation from India and to three prison sentences in Britain.

Even in his lifetime Scott was a mysterious and paradoxical figure: an ordained priest who worked, briefly, as an agent of the Communist Party, an admirer of Gandhi who trained as a rear gunner in the RAF, a modest orator who once held a committee of the United Nations spellbound. Unlike Trevor Huddleston and Canon John Collins, both of whom regarded him as their inspiration, he was accorded little honour by the Church of England, perhaps because he so resolutely insisted on practising what his superiors were content to preach.

Although Scott was loved and admired by all those he sought to help and by those who supported him – he gave away such worldly goods as came his way with almost reckless abandon - his friends and fellow campaigners were often frustrated by his apparent inability to accept the intimacy which they offered. Tragically, it was only as he lay dying that he could bring himself to admit to his oldest friend and mentor that his personal life had been blighted by the abuse he had suffered as a child.

In this extraordinary biography, with an introduction by Desmond Tutu, Anne Yates and Lewis Chester bring to life a man who strove to bring liberation to millions, but was himself held captive by fear and doubt.