BEN BAILEY SMITH is not the first rapper to take a lead role in a cop series. Ice-T is a regular in Law & Order: Special Victims Unit in the US but he is the first in UK TV history.

Smith first found fame as Doc Brown, a rapper and comedian, and retains the name for his work in those fields. But since 2011, he has gone by his birth name for his acting work.

Law & Order: UK features his biggest role to date. He joined the cast at the start of the current run, playing DS Joe Hawkins and loving every minute of it.

“When I was a little kid I wanted to be an action hero and this is the closest I’ve ever come to that,” says Smith. “So it is a lifetime dream-type deal.

“Sometimes when I’m running after an assailant during filming I think, ‘I used to do this in my head on the way to school when I was seven’. The element of it is beyond satisfaction, it’s very exciting for me; a big, big deal.”

Smith feels he can relate to Hawkins too. “He had grown up in care and hung and knew a lot of criminals before getting into police work. Joe has an affinity with troubled kids and difficult boys. It reminded me of my past; my mum was a youth worker and then became a social worker, and my first jobs were volunteering with kids in care.

“There are lots of parallels between me and Joe, but the crucial difference is he would go head first into battle with a man with a gun, whereas I would turn tail and run as fast as I possibly could in the other direction.”

There are also parallels between Joe’s relationship with Ronnie, and Smith’s with co-star Bradley Walsh.

“As Ronnie was handing down wisdom to Joe in the script, I was learning so much from Brad off set,” he says.

“He was encouraging me to improvise with him at the top of scenes to get into character, and the resulting freshness of exchanges and joking with each other, the gallows humour, was great.”

There could be a lot of that going on in this episode, which begins with the discovery of a blood-spattered hotel room and a stolen credit card that belongs to wealthy, upper-class man Charles Hutton.

No corpse is found, which begs the question: where did the blood come from? Further investigation suggests that Charles’ beloved daughter, Georgia, the apple of his eye, gave birth in the room. The baby can’t be found, but charges are brought against Georgia and her boyfriend Rufus anyway.