Kenneth Branagh has admitted that playing tormented TV detective Wallander put him in a “permanent, acceptable state of anxiety”.

The Belfast-born actor and director told the audience at film industry event Cannes Lions that appearing in the role felt like “an open wound.”

Branagh also said that playing Reinhard Heydrich, the Nazi architect of the Final Solution, in the TV film Conspiracy led him into "a depression".

He added that exposing layers of hidden emotion was unavoidable in his approach to acting. “As I get older it gets under the skin more . . . I don’t leave it at the office as much as you wish you could.”

Branagh also revealed that he meditates twice a day for half an hour at a time “to calm that racing mind.”