Idris Elba reckons playing TV detective DCI John Luther has been the toughest role of his career to date.

The actor regards the maverick investigator as the most demanding character he has played, despite a CV that includes bleak roles such as the soldier seeking retribution in psychological film thriller Legacy and an iconic drug dealer in HBO’s The Wire

“Emotionally and physically I can’t play Luther slouching,” Idris said. “He’s not a comedian, there are no jokes, so I come home from work and I have a headache. It’s sometimes quite depressing.”

But the star reckons tortured souls are “definitely interesting to play”. He added: “We all have demons and in these [roles] I can exorcise my own demons as well.”

The disturbing and brutal nature of Luther meant the show created much debate when it first aired. “There was certainly a shift in the way Luther was received,” said Idris.

“People were like, ‘This is BBC trash’ but by the middle of the series they were loving it. I think we even got a retraction, which is unheard of. I thought that was cool.”

Luther returns to BBC One on Tuesday, June 14.