Nine years ago, Graham woke up and discovered he was dead.

He was in the grip of Cotard's syndrome. People with this rare condition believe that they, or parts of their body, no longer exist.

For Graham, it was his brain that was dead, and he believed that he had killed it. Suffering from severe depression, he had tried to commit suicide by taking an electrical appliance with him into the bath.

Eight months later, he told his doctor his brain had died or was, at best, missing. "It's really hard to explain," he says. "I just felt like my brain didn't exist any more. I kept on telling the doctors that the tablets weren't going to do me any good because I didn't have a brain. I'd fried it in the bath."

Doctors found trying to rationalise with Graham was impossible. Even as he sat there talking, breathing – living – he could not accept that his brain was alive. "I just got annoyed. I didn't know how I could speak or do anything with no brain, but as far as I was concerned I hadn't got one."