Coronation Street star Daon Broni has told RadioTimes.com of the turning point for character DI Costello amid Becky Swain’s (Amy Cudden) disturbing behaviour.

As viewers have seen, Becky returned ‘from the dead’ in September, revealing to her estranged wife Lisa (Vicky Myers) that she was living under a false identity in Spain after landing in some hot water at work.

Costello helped her escape, even passing off the body of a hit-and-run victim named Tia Wardley as Becky. He even paid a woman to pose as Tia when Lisa and fiancée Carla Connor (Alison King) went digging for information.

Now that Becky’s back in the country, she poses a huge risk to Costello’s professional life. His career would crumble should this corruption come to light.

In tonight’s episode, desperate to get her feet back under Lisa’s table and oust Carla from their lives, she claimed that she was being tormented by an unknown assailant and needed to seek refuge at No. 6.

Carla was less than impressed to have her love rival kipping under her roof, while Costello was furious to hear that Becky hadn’t boarded the flight to Spain that he’d booked.

Meeting in an alleyway, he warned her that if she didn’t comply with his demands, he’d have her killed in the same way he got rid of Tia Wardley.

But will he follow through with the act?

“I’ll leave that for the people to decide,” Broni explained.

“He’s said that he would do it, and to think about it, he’s got a family – a daughter and a wife – so one side he absolutely would [kill her] to protect them, but on the other side, is the threat of him saying he’s going to do it enough?”

He laughed: “I don’t think I’ve ever played a nasty character in the way Costello’s developed, but I always knew my hidden villain was there! I knew that I could do it.

“It’s been nice to play Costello because I don’t think he’s an obvious villain, it’s just threats and a mental game that he plays. It’s been interesting to play that side of him.”

To Costello’s surprise, Becky then hit back by asking about his 12-year-old daughter, Lacey – a thinly veiled remark that implied she would take extreme measures to stay in Manchester. Heading home, she scoured the child’s social media.

Would Becky really seek out Lacey?

“The second that Becky brings Costello’s daughter into the situation, for him that changes things. There’s an actual personal risk to his family,” Broni continued.

“It definitely ramps up his reason to go through with it. There’s massive risk and it’s the thing he’s most aware of. He needs to keep his family safe.

“This is a DI who is speaking like this. It makes it even more fantastic that he’s uttering these words and making these kinds of comments.

“He’s in a position of authority in the community and it’s interesting to play that dynamic.”