A grave drama to recreate.

Stephen Tompkinson has had some challenging roles in his career, from charismatic priest in Ballykissangel to maverick undercover cop in the BBC crime drama In Deep.

But nothing could have prepared him for the eerie sensation he felt when returning to the scene of a horrendous crime which took place in a cemetery in Bakewell, Derbyshire, more than 30 years ago.

This is where, in broad daylight typist Wendy Sewell was brutally attacked with a pickaxe and sexually assaulted. Several days later she died from her injuries. A 17-year-old council worker, Stephen Downing, was convicted of her murder and sentenced to life imprisonment in 1974.

But his refusal to admit his crime meant he was classified as IDOM (In Denial Of Murder) and ineligible for parole.

Years later, local journalist Don Hale became involved after he was approached by Downing's parents. Hale tirelessly campaigned for Downing's release for six years and, largely through his efforts, the conviction was overturned on a technicality in 2002 after Downing had served 27 years in prison.

However, it was never a clear-cut case. One year on, Derbyshire police announced that, following their exhaustive reinvestigation of the murder, the only remaining suspect in the case was Downing.

In the new BBC One two-part drama, In Denial Of Murder starting on Sunday, Tompkinson, 38, plays Hale, the campaigning and obsessive journalist who fought for Downing's freedom.

Filming in and around Bakewell stirred up a lot of interest among the locals, says the actor.

"The town still bears the scars of that day. It was a 50:50 split between the people who thought the police had got the right man and those who didn't.

"Some don't want to hear Stephen Downing's name mentioned and didn't want their licence fees wasted on the BBC doing a film of it.

"The cemetery itself was very eerie. I went up there a few weeks before we started filming and it's bizarre to think that this brutal, violent crime happened in the middle of the day and nobody saw anything."

Tompkinson himself has not reached a conclusion about the case.

"Because I can't find a motive for Stephen, knowing he was 17 at the time with a reading age of 12, it seems completely out of character for him to see someone and then, malice aforethought, pick up a pickaxe handle and hit them nine times. The first policeman on the scene didn't know if the victim was a man or a woman."

He has not met the Downings or Don Hale, because he felt that might just muddy the waters.

"It's the first time I've played anyone who's living," he says. "Consequently, there was an awful lot of material available to research and I found myself getting a bit bogged down with it.

"It clearly wasn't fair, what happened to Stephen. The police treated him badly. They know themselves that they did wrong because the conviction was overturned on account of being unsafe."

And what of Don Hale?

"I don't think he knew what he was taking on when Stephen's parents approached him. I don't think it was until he met Stephen face-to-face that he believed him so completely."

Aside from his latest project, Tompkinson is certainly not short of work offers, which include a West End play, a movie in Canada and a new six-part series for the BBC.

"I just try and do something completely different from the last job because hopefully if I'm not bored with the variety of work, be it changing mediums or doing theatre or radio, then hopefully the audience won't be bored."