Post-Office account

Mackenzie Crook is very happy. 'I'm having the time of my life,' he says about One Flew Over The Cuckoo's Nest, the now infamous Edinburgh adaptation of Ken Kesey's cult novel, which hit the West End last week. 'The company is really strong now, we've pulled together.'

It could have been very different. Cuckoo's Edinburgh rehearsal difficulties have become the stuff of theatre lore - absconding directors; rumoured personality clashes between various cast members and Christian Slater's chickenpox, which put him to bed days before the production was to open.

'I don't think anyone doubted we had a good show,' Crook says now. 'But we did wonder if the press would give us a hard time because of the problems.'

Crook talks a bit like he looks - hesitantly, with the same stumbling concentration one might associate with a ten-year-old child.

Yet his awkwardness belies an intelligent sensitivity that positively radiates from his performance as Billy, the damaged, stammering teenager.

'All the characters I've played recently have been quirky or fools,' Crook says. 'I wanted someone with complexity. Billy is a big symbol of Nurse Ratched and Murphy's struggle for control. I find it very traumatic.'

Crook has been lucky to have escaped so quickly the character of Gareth, the emaciated nerd from The Office, which catapulted him from the obscurity of late-night comedy to the Golden Globe awards.

Some actors find it hard to shake off the role that launched their career; Crook had the matter taken out of his hands. He was cast in Pirates Of The Caribbean when its director watched The Office while flying across the Atlantic and, since then, his unconventional looks have found him working alongside some of Hollywood's most beautiful people, including Matt Damon, Christina Ricci and Al Pacino.

He is aware that when he is called to an audition, it's partly because the part requires a particular 'face' - Crook looks half-angel, half-ghoul - but he is equally wary of being typecast as the oddball support role. Certainly he exerts a fascination over Joe Public: 'I would be walking along the street with Christian and people would whisper to their friends when they saw him but, with me, they would laugh and point.'

Even though Crook began his career as a stand-up, partly as a means of escaping the Dartford treadmill of dead-end jobs, he admits he is not naturally funny. 'I don't do witty. My stand-up was always heavily scripted and I could only just about handle hecklers.' His comedy alter ego Mr Bagshaw was more about perfecting the art of character acting than making people laugh. He has no plans to go back but says that the years on the live circuit were a brilliant preparation for theatre.

'I didn't go to drama school so I've no formal training but I've had to handle some unbelievably awful audiences, which was an education in itself.'

He's also had to cope with some of the worst reviews ever committed to paper with The Sex Lives Of The Potato Men - the 'comedy' he made with Johnny Vegas. That was a disaster from which he has somehow emerged unscathed. After Cuckoo, he jets back to America for two Pirates Of The Caribbean sequels with Depp again.