'Tinker, Tailor, Soldier, Spy' actor John Hurt thinks he would make a "terrible" secret agent.

The 71-year-old star - who plays a character in charge of Her Majesty's Secret Service in the forthcoming movie alongside Benedict Cumberbatch, Colin Firth, Gary Oldman and Tom Hardy - explained he would be "too transparent" to have his alter-ego's job in real life.

When asked whether he would make a good boss of MI6, he told The Guardian newspaper: "I'd have been terrible! Too transparent by half!"

John admitted he found the movie - an adaptation of classic spy novel by John le Carré - tough to follow at times, and thinks viewers will need to concentrate when they are watching it.

He added: "I need to see it again. But even when you're losing the thread a bit you never lose interest in the film.

"Of course I have to think: is that just because I'm in it? If I were watching it in an auditorium would I just think: f**k this, I'm out of here? But I don't think I would be. It's not easy. You have to sit up straight."