DS Sarah Collins is back in The Tower

Gemma Whelan is back as DS Sarah Collins in The Tower, but anyone who watched the first series of the crime drama may notice that this time, she looks a little different – for a start she’s ditched her signature orange duffle coat.

The actress says: “We did give the duffle a moment, but it ends up being left in the back of Sarah’s car.

“It was quite difficult last season because I was pregnant so they had to try their best to cover up a woman who clearly would not have children at this juncture in her life.

"This year everything that [costume designer Darren Finch] brought along felt like Sarah.

"It was great to be able to move it on without doing anything drastically different. She’s looking smart and the clothes aren’t getting in the way. But there is no more orange duffle coat.”

That’s not the only thing that’s changed. Sarah has now moved to Homicide Command, where the team are busy looking for the culprit behind a shooting in a chicken shop – which makes it all the more frustrating when her new boss lumbers her with a cold case involving a teenage girl who went missing 25 years ago.

Gemma, whose previous credits include Game of Thrones, The Moorside and Upstart Crow, says: “She would definitely like to be part of the chicken shop shooting case, and she knows that being handed a 25-year-old cold case is a thankless task which everyone, especially her new boss, expects her to fail.

“But I think she rises to the challenge. She thinks outside the box and fairly quickly – just by looking at people, thinking about people in a different way – she develops a vital new lead.

"She prides herself on that. Even though she knows she’s being disrespected, she says ‘Right, I’m going to prove myself, I’m going to crack this.’”

But while she may have a new investigation to get her teeth into, the events of the previous series continue to haunt her.

Not only is her colleague DC Steve Bradshaw (Jimmy Akingbola) part of her new team, but she learns that PC Lizzie Adama (Tahirah Sharif) has been cleared of misconduct and is back at work, which Sarah has mixed feelings about.

Gemma says: “She knows that a crime was covered up – by police officers – and she knows Lizzie Adama was part of it. At the same time, she understands why Lizzie acted as she did and the pressures she was under.

"Almost despite herself she’s impressed that Lizzie stayed in the police and now she’s waiting for her to prove herself.”

Lizzie’s first chance to prove she can do things by the book comes when she is called to a report of domestic violence at the home of a couple and their six-year-old daughter. But when the case takes a tragic turn, it brings her into contact with Sarah. Can they put the past behind them and work together?

We won’t have long to find out as the four-part drama is showing over consecutive evenings.