Marty (not his real name) was one of Karen and Steve's first referrals. Then aged 17, he arrived with a warning from probation officers who said he was notoriously difficult and heavily into offending. Eighteen months later, Marty is a youth worker and studying to be a social worker.

The story of his childhood - like that of many young offenders - is grim. His mother was mentally ill. When Marty was four years old, a foster father bullied him every day for a year before stuffing him into a plastic sack and trying to bury him in his allotment - at which point the police intervened. He spent the rest of his childhood ricocheting round his family, then to a home and from there to an assessment centre, where he was told he would be kept for two weeks but was to remain for more than two years. By that time he had become involved in drugs and stealing cars.

He says now: 'By then I was the most rebellious kid you could think of. I hated anyone over 18. Then I got charged with 12 offences, and it all came to a head.'

Marty was sent to a young offenders' remand centre. There were two men on the bunk bed and one on a mattress on the floor in his cell. One was in for drugs offences, the other for burglary. They were locked up for 231 2 hours a day. Bullying was rife and his two weeks there seemed like a life sentence. But an enlightened judge gave him the chance to go to remand foster carers.

Steve's sense of humour and bluntness shocked the hardened young offender. The only rule was that he must keep his curfew, but Marty says: 'He gave me boundaries. I never got in trouble once while I was there. He turned me right round.'

It was not an overnight conversion, however, and Marty was in and out of trouble until a year ago. But Steve and Karen visited him in prison and collected him when he left. They still help him out financially and continue to give him moral support.

Marty, who has four GCSEs, is studying on an NVQ social studies course and has a job in youth care. He aims to be a director of social services so he can change the system. 'If people tell you that you are doing well, you want to do better and better, but if people are telling you you're rubbish, that's what you become. Mates write to me now wanting me to do bank jobs, but I write back and say: 'Sorry, I've got a life'.'