Shameless star David Threlfall set for crime role in Code of a Killer

David Threlfall’s killer instinct.

He’s been the ultimate sofa-bound layabout, shown the darker side of one of the nation’s comic geniuses and played Ark-builder Noah.

And the versatility of David Threlfall Frank Gallagher in Shameless is now being showcased in Code of a Killer.

The second part of ITV’s big new drama airs this week with the gripping conclusion to the tale of DNA bringing a murderer to justice for the first time.

John Simm is Dr Alec Jeffreys, the Leicester University scientist who invented the remarkable technique to read each individual’s DNA fingerprint.

And David is Detective Chief Superintendent David Baker who used it not only to find the brutal killer of schoolgirls Lynda Mann and Dawn Ashworth but also free a falsely-accused teenager.

“It was just a fascinating tale,” says David of the appeal of getting on-board the ITV drama.

“You have one man working on investigating genetic fingerprinting and, not many miles away, a policeman who wonders if that could help him find a murderer.

“It was a world first happening right here in Britain and it was a lot later than you might think, just the 1980s.”

David says he got a real sense of the detective ready to turn to technology when he caught up with Baker before filming started.

“I wanted to find out what kind of man he was as well as how he went about his job,” confides David.

“He struck me as a good, honest, straightforward man who was pretty obsessional about finding a killer.

“He was in the forefront of using tape recorders in interviews and using computers to get information quicker. But I don’t think he had a feeling of creating history.”

Playing real life characters comes naturally to 61-year-old David whose rich CV includes portraying both Prince Charles and Prince Phillip.

But one of the most scrutinised came in Tommy Cooper: Not Like That, Like This.

It was a warts-and-all picture of the man whose comic skills delighted a nation but had more than a few troubles away from the public gaze. And David admits it wasn’t the easiest of jobs.

“Everywhere he went people thought he was the funniest man in Britain well I’m clearly not,” smiles David.

“So that side of him was actually harder than what you might call the dark side or just the more private man.

“I had to watch as many performances of him to try and sponge as much as I could of the magic tricks and the way he could be so funny without opening his mouth.

“Everyone does an impression as well as have a sense of what he was like. So you’ve got to spend every waking hour you can get practicing.”

And David knew he was being judged not just by the viewing public but Cooper’s family too.

“Being trusted to do it was an honour,” explains David. “I met his daughter Vicky who gave her blessing to the script and to me playing him.

“It was his life from 1967 until the night he died and you don’t want to dishonour the memory.

“In a way it’s the same as honouring the memory of the two unfortunate victims in Code of a Killer for the families.”

David, who also recently starred alongside Jude Law in big screen thriller Black Sea, admits ringing the acting changes is vital.

And The Ark, the 90-minute Biblical epic shown at the end of last month, is a perfect example.

“It just keeps me interested I prefer pretending to be other people as opposed to being me all the time.”

For the best part of a decade David was the boozy, mouthy Frank in Shameless. And puffing away on an endless supply of fags was just one challenge for non-smoker David.

“You’ve got to get it right,” adds David.

“Smokers can tell if you’re not really doing it and it ruins the illusion and stops people believing in you. So you’ve got to make them your friend for a bit. Thankfully they were all herbal.”