WHEN Martin Compston flicks through his wedding album in years to come, it wouldn't be surprising if a fleeting thought of notorious Lanarkshire serial killer Peter Manuel flits into his mind.

The 32-year-old actor plays Manuel in the much-anticipated ITV drama, In Plain Sight, which charts the two-year murder spree that claimed at least eight lives between 1956 and 1958.

Getting into character as Manuel – known as The Beast of Birkenshaw – meant looking the part.

"The barnet is pretty incredible," says Martin, touching a hand to his head. "I got married the day before we started filming. Manuel had this iconic bouffant so I wasn't allowed to cut my hair.

"There was that wee thing of having to say to my wife: 'Look darling, we are not going on honeymoon and I'm going to have shocking hair …'

"It is a pretty intense haircut. It took 40 minutes to have it blow dried and styled. But as soon as it's up and the jacket is on, you do feel like you are him.

"They probably would have allowed me to wear a wig but they are f***ing annoying," he adds. "Maybe when I look back at my wedding pictures in 10 years I won't agree, but at the time I thought I would rather have one day like that than seven weeks of a wig pinned to my head."

Filmed on location in Glasgow, the three-part series focuses on the cat and mouse game between Manuel and police detective William Muncie, played by Douglas Henshall. Manuel reportedly went to great lengths to taunt his pursuer, leaving tantalising clues and even sending birthday cards.

"People accused Muncie of being obsessed because they thought Manuel was just a fantasist," he says. "That was one of the reasons he got away with it for so long. The script is not really about the murders per se, but more about how Manuel was taken down."

What was it like to get inside the mind of a serial killer? "It has been difficult because he was so evil," he says. "If we didn't put 'based on true events' at the start, you wouldn't believe it happened.

"A lot of people will have heard of him and knew he was the bogeyman, but it isn't until you read up on the depth of his crimes that you realise just how violent in nature Manuel was. The guy was a psychopath in every sense. That word gets thrown about, but he had no empathy."

Martin found listening to music also helped him get in the zone. "I Wanna Be Adored by The Stone Roses really resonates with Manuel because he loved the acclaim," he says.

"There are a lot of different shades to him. It is a bigger challenge and I had to sit down and think about it a bit more.

"But there is something nice about sitting in your room by yourself with the curtains drawn and trying to write like him, going through scripts and trying to make choices.

"It's a bit dark and perhaps self-indulgent but in a way you feel like you've earned your money."

However, the Greenock-born Sweet Sixteen and Line of Duty star was equally conscious of reining himself in at times.

"Just purely in acting terms it is a gift of part," he says. "Sometimes it is easier when you're acting if you have something to really go for. You have commit to it.

"The only thing is that you worry about going too far with it because it could become pantomime evil because he was that bad.

"When you are reading some of the stuff he has done and you are playing it, you are thinking: 'Are people going to believe this?' but that is just how wild he was."

Martin has played his share of bad guys including an electrifying turn as gangster Paul Ferris in The Wee Man.

"Manuel was a lot darker because I think Paul would probably say that for him it was about money-making. I'm sure in his time that he took some enjoyment out of his job, but it was more for financial gain.

"Whereas with Manuel it was just blood lust. He enjoyed killing. It wasn't pinning the girl down and doing whatever, it was seeing the fear in the eyes that would turn him on – which is actually even more terrifying."

"He wanted to terrify people and took enjoyment out of that. He went back to crimes he committed afterwards because he didn't feel he had enough joy the first time or that it was too rushed."

While Ferris visited the set during filming for The Wee Man, Martin admits to being grateful Manuel isn't around to see his portrayal.

"Don't get me wrong, it's a good thing Manuel is not alive but there will be relatives of victims. These were real people that these things happened to.

"Even Manuel's family, I'm sure they didn't have the best of times and that their lives were made a misery after it.

"You are always aware that you have to treat it with a certain amount of respect."

In Plain Sight begins on STV, Wednesday, at 9pm