Lemn Sissay has spent the past two years seeking redress from Wigan council for his childhood in care. “I’ve heard some people have committed suicide going through the legal process and I can understand how it could happen. I didn’t know it would be so violently intrusive into who I am. You’re sailing so close to the storm. You’re playing with a breakdown.”

Earlier this month, two years after the award-winning poet, playwright and broadcaster made his compensation claim, and in a last-minute attempt to avoid an expensive court case, the council and its insurer finally agreed to award Sissay a six-figure sum, along with a formal apology. “You ask for redress because of your own sense of self worth. It wasn’t good enough for me as an artist to go banging on about my story without getting the institution that was my parent to recognise it on its own terms.”

Sissay has made several documentaries about the search for his family and his 25-year battle to get hold of his files from Wigan social services. He grew up in care even though his mother, a young upper-class Ethiopian who came to Britain to study, wrote letters begging the council to return her baby once she was better able to look after him. Her requests were ignored. Instead, he was renamed Norman by a social worker called Norman and permanently fostered by a local white family of devout Christians.

When Sissay hit adolescence and became a bit rebellious (staying out late, eating cake when he was forbidden to do so), his foster parents told him he had the devil inside him, returned him to Wigan social services like he was an overdue library book and stopped all contact, leaving him isolated from everyone he had ever known. He was 12 years old.

Over the next five years, he lived in four different children’s homes, ending up in the notorious Wood End assessment centre, where he says he was imprisoned, bullied and physically abused by staff. At 18, he left the care system, in shock, without a penny to his name or any qualifications. He would not be reunited with his birth mother until he was in his late 20s.

“In the past, reading my files from social services, I’ve said it made me feel like I was a rat in a laboratory experiment. Now, I feel like a lion. I feel like a warrior,” he says.

The council’s financial settlement was based on the difference between Sissay’s low earnings for almost two decades after he left care (when he worked, for example, cleaning gutters) and the wage earned by the average UK worker.

“That was the only way the lawyers would calculate it, which is ridiculous,” he says. “Had we not settled, the council would have dragged people from my past into court and argued I was a liar. They were going to get their psychologist on my case: a man who is known for tearing people apart.

“The effects of that could have broken me. I’m aware they already broke me as a kid and so my life as an adult is about acknowledging that and mending. A legal case like this involves digging into the most shameful parts of your past and trying to prove what people did to you. Psychologically, it’s a nightmare.”

At the same time, his bid for legal redress was about becoming the man he always knew he was. “Institutional shame is very powerful, because it is insidious. It works its way into you to make you believe it. A lot of kids in care think they deserve the shit they get. The best thing I ever did was go into therapy.”

Battling this irrational sense of shame about what happened to him was one of the reasons Sissay wanted his life story to be investigated by lawyers and shared with the public. Last year, he even decided to share, in a one-off stage performance entitled The Report, the deeply distressing psychologist’s report that his own legal counsel was submitting.

“It has been quite useful to feel supported by a country and I do feel strongly supported now,” he says. But it was a different story when he came out of care and needed help getting on his feet. “They said: ‘There’s no dark journey that you’ve been on. Just get on with your life and become a responsible adult.’ Nothing was accounted for.”

His going public has allowed other people to bear witness to Sissay’s story, and settling his case means he will finally have full access to his files without any of the redactions that kept names and other secrets hidden from him for years.

“My life is full of known unknowns. When I left care I realised I didn’t know anyone who had known me longer than a year. Making me relative to no one was Wigan council’s biggest crime. So I became the lithograph. I had the negatives of what had happened but nobody else had the picture. I didn’t have witness because witness is what happens in a family.”

He says he knew he had to do everything humanly possible to find redress. He had made promises to himself as a child that he had to keep. “Like in Hansel and Gretel, I had laid down pebbles so I could say: ‘This is the darkest place I’ve ever been, but I’m here and I am a child and here is the pebble.’ I knew I’d come back and shine light into that dark space, that horrible cave, and say: ‘This is what they did to me.’ The end of my court case is the echo, coming from that cave, out into the bright sunshine.”

He plans to use the compensation as a mortgage deposit and, at 50, buy himself a home he can call his own. He also hopes his story will be an example to others. “Councils have insurance for cases like mine, but I wanted it on their financial records. I wanted them to feel some of the tremor I felt. The child in care is the most ignored child in society.”

Every social worker, every psychologist, every foster carer, every cleaner in a children’s home … Sissay wants them all to know that children in care need them, but equally, they need to be on their game.

“If they abuse us, we are going to come back. And we are going to make them pay for it.”