Adam Darski was rushed to hospital in 2010, forcing the cancellation of two tours. Two weeks later he was diagnosed with leukaemia, and underwent a bone marrow transplant. He confirmed he was returning to health the following year.

In his book Confessions Of A Heretic, to be published in English on March 19, Nergal says: "Tuberculosis was first on the list. I thought that wasn't the worst possible scenario. Then it got worse - the doctors said it could also be lymphangioma or HIV.

"When I saw these last three letters I felt weak. Suddenly, flashing before my eyes like a twisted highlight reel, were all the sexual encounters of the last few years. There were quite a few, but as far as I could remember I was always careful.