"It has kept me sane," he says.After working his way up the local-authority ladder, he took over as Hackney's director of education in 1989 "I knew it was going to be challenging," he says. The report denounced local anti-racist policies which, it argued, did little to help ethnic-minority children.He is still involved with a biannual book fair for radical, black and Third World books and is helping to set up a black-history archive. He started a mobile bookshop selling books on race and by black authors and was one of the authors of Murder in the Playground, a controversial report on the stabbing of a 13-year-old Asian pupil at the city's Burnage High School. He split from the Dominicans (he was a friar from 1964 to 1967) because of the Church's links with South Africa, and while gravedigging by day in the late 1960s he worked in an inner-city youth club by night.Later, in Manchester, he ran a black parents and teachers association.

"There's a fundamental issue about quality education for people in working-class areas and inner cities."He sees education as a means of delivering the social liberation for which he has always fought. His parents were illiterate peasant farmers and as a scholarship boy he learnt the power of education. What marked him out from his peers was his mother's determination that he should have the opportunities she had not had. "There were lots of other kids around my village who had as much ability but weren't able to progress because their parents didn't have the money to send them to particular kinds of schools," he says.

His opponents, he argues, did not share his view that the only true liberation for black children lies in the highest-quality education.Mr John was born in Grenada, West Indies. And it was here that the smears and taunts against Mr John started.Now he has thrown in the towel: last week, after three months on sick leave, he took early retirement at the age of 51. He will continue to pursue an industrial tribunal action, claiming that his employers failed to defend him from attacks by left-wing teachers and gay activists.So how did it come to this? How did this black-rights activist become so unpopular with people who ought to have been his natural political allies?His real troubles began in April 1995 when a coup within the ruling group moved Hackney council sharply to the left. It was here that a storm broke over the primary school head Jane Brown, who refused tickets for her pupils to attend a performance of the Romeo and Juliet ballet because it was "entirely about heterosexual love".It was here, too, that Hackney Downs comprehensive became one of the first schools in the country to be closed down on ministerial orders. Even now, the walls of his study, in a large terrace house in a rundown part of north-east London, are decorated with posters from recent productions by black theatre companies. But nothing prepared this sometime gravedigger and Dominican friar for his seven stormy years as head of education for the London borough of Hackney.It was a council, he says, where elements of the Labour left brought it close at times to mob rule. When he worked in Manchester, he spent the night of the 1981 riots ferrying people between Moss Side police stations and hospitals.