The artist Peter Howson believes he has it in him to commit murder.

Howson, who famously painted a nude portrait of Madonna, admitted he had been violent in the past.

He said: "I once walked down Sauchiehall Street (in Glasgow) at midnight, thinking that people were skittles and decided to knock as many people down as I could. That was one example, years and years ago."

Howson, 50, who studied at Glasgow School of Art, said "It's there, but it's under control, I'm positive about that."

He said one reason for this was he suffers from Asperger's syndrome - a form of autism.

During the Balkans conflict Howson became the official British war artist. He said: "To put a person with Asperger's in a war situation is asking for trouble."

Howson converted to Christianity in 2000 while being treated for alcohol and cocaine addiction.

"I'm really devoting my life now to helping people who are in the same condition and who are in trouble," he said.

"I change people through having them in my studio, meeting them and talking to them. It's like rehabilitation through action, rather than words."