Depression hit Rowling when her first marriage to a television journalist broke down after just two years. She had moved to Portugal to teach English and gave birth to her first daughter Jessica. She said: “I’d had a short and quite catastrophic marriage. “I had to get my baby back to Britain and re-build us a life and adrenaline kept me going. “It was only when I came to rest it hit me what a complete mess I had made of my life. That hit me quite hard. We were as skint as you can be without being homeless and at that point I was definitely clinically depressed. That was characterized my a numbness, a coldness and an inability to believe you will feel happy again. All the color drained out of life.”

Rowling hit an all-time low when she convinced herself something awful was destined to happen to her two-year-old daughter. She said: “I loved Jessica very very much and was terrified something was going to happen to her. “I’d gone into that very depressive mind set where everything has gone wrong so this one good thing in my life will now go wrong as well. “It was almost a surprise to me every morning that she was still alive. I kept expecting her to die. It was a bad bad time.”

Film crews took Rowling back to the flat a few miles from Edinburgh where she overcame depression by writing first novel Harry Potter and the Philosopher’s Stone. Tears began to flow as she walked into the small lounge room where she first put pen to paper. She said: “This is really where I turned my life around completely. My life changed so much in this flat. I feel I really became myself here. Everything was stripped away. I’d made such a mess of things. I just thought I want to write so I wrote the book. What was the worst that could happen? It could get turned down by every publisher in Britain. Big deal.” As she walked into the bedroom she spotted the whole Harry Potter series on the current owner’s bookshelf. “If it all disappeared this is where I would come back to,” she said. “Because it’s such a well worn part of my story now it’s a big yawn to hear how I wrote it as if it was some publicity stunt I did for a year, but it was my life and it was very hard. “I didn’t know it was going to be this fairy tale resolution. Coming back here is just full of ghosts.”

Rowling revealed how she wished to be a writer since her childhood but says she never expected the fame that has come with it. “I wished to be published and I wished more than anything in the world to be a writer,” she said. “It never occurred to me in a million years that people would search my dustbins, put a long lens camera on me on the beach or bang on the door of one of my oldest friends and offer her money to talk about me.” Rowling has ruled out writing any more Harry Potter books but let slip she is working on a new novel. “It’s definitely time to stop now. I don’t want to write any more Hogwarts books,” she said. “I’m happier now than I’ve ever been in my life.