British actor Ben Miller has opened up about struggling with obsessive compulsive disorder (OCD) when he was younger, saying at times it became “unmanageable”.

The 55-year-old star plays Jasper Tempest, a genius and eccentric Cambridge University criminology professor who suffers from OCD and has a tortured past, in new crime drama Professor T.

His own experience of the disorder helped with his performance, he told the Radio Times.

“I did struggle a lot with OCD, particularly in my twenties, and I’m very lucky in that it’s all very manageable now,” Miller said.

“But there were times where it was unmanageable, as it is for Professor T, so I know how that feels and I know how I dealt with it.

“I’ve found these sequences – where in the Professor’s imagination he doesn’t have OCD and he’s free of all those behaviours – are a great way to show what’s going on inside.

“Seeing somebody lining up items on a desk looks pretty innocuous but inside, that person can be a lot more complicated.”

OCD is a mental health condition where a person has “obsessive thoughts and compulsive behaviours” and it can cause “feelings of anxiety or unease”, according to the official NHS website.

Miller, who rose to fame in the 1990s as one half of the comedy duo Armstrong and Miller, with Alexander Armstrong, and is also known for Bridgerton and Johnny English, said he had a personal obsession with numbers and that touching things was a tactic to control his anxieties.

After reaching crisis point, he sought professional help, he said.

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“I was very OCD about doorways and doors. For me, it was a way of mitigating and controlling my anxieties. I thought if I touched an object a certain number of times, then bad things won’t happen. Of course it doesn’t work – I constantly had to amplify my behaviours to try and reduce my anxiety.

“There comes a point where the OCD behaviours themselves make the anxiety worse and you enter into a positive feedback loop; it gets out of control. There were crisis points when I decided to seek professional help.”

Professor T, a six-part ITV drama based on the hit Belgian series of the same name, was filmed in Belgium and Cambridge, where Miller went to university and began his acting and comedy career with the theatrical group Footlights.

“There was the strange sensation of feeling life had come full circle, my house in this show is where I wrote some of my first comedy sketches,” Miller said.

The series also stars Frances de la Tour as Jasper’s mother, Adelaide, Emma Naomi as Detective Inspector Lisa Donckers, and Barney White as her police sidekick Dan Winters.