As Unforgotten reaches its conclusion, fans are still scratching their heads, wondering whodunit

For some, stardom arrives early, and they’re thrust into the limelight at a young age, while for others, it comes much later in life.

The latest run of Unforgotten, which ends this Monday, has featured an actress who has experienced one of those, and an actor who is dealing with the latter.

Hayley Mills was a child star in the 1960s thanks to films such as Whistle Down the Wind, The Parent Trap and Pollyanna, winning a special juvenile Oscar for the latter. Her grown-up career hasn’t been as successful, but she’s continued popping up in projects occasionally, including in a few scenes of the acclaimed crime drama as the wife of Tory peer Lord Anthony Hume.

Playing Hume is Ian McElhinney. In contrast to Mills, he came to showbusiness late, having had a career as a teacher in East Yorkshire before treading the boards professionally. Now 74, he’s become a familiar face in recent years due to his memorable performance as Granda Joe in Derry Girls; he’s also popped up in the likes of Game of Thrones, The Split, Doctor Who and The Outlaws.

The duo had never worked together before, but it seems they got on well.

“She’s lovely,” says McElhinney of Mills. “Of course, I remember when she was a young girl in the various things that she did, so it’s like you’re working with a bit of a screen icon.

“We shot all our stuff together in one week, because it all took place in the one location, which was the family home. It was not exclusively, but primarily, the two of us, and it was a good vibe. That was my first working week on the show, and I really enjoyed it.”

As regular viewers know, Hume is one of the main suspects in the case being investigated by the team led by Jess James and Sunny Khan. He certainly seems to have plenty to hide – and a lot to lose; we’ve seen him trying to seal his legacy before succumbing to terminal cancer.

“Outwardly, he probably wants to be remembered in a certain way. Inwardly, he’s probably desperately trying to compensate for some of the things he’s done in the past,” says the actor before commenting on the others in the frame for the murder of Precious Falade, whose remains were found stuffed into the chimney of a house under renovation: “It’s fascinating because they’re such different types from such different worlds. How do they all tie up?

“It is intriguing, but they’re great plots and they’re well layered, and there’s a question mark over everybody. At one point you might be leaning one way, or you might be leaning another way, and ultimately you don’t know until the end. And that’s how it should be.”

As the series reaches its conclusion, fans are still scratching their heads, wondering whodunit.

“They’ll not learn anything from me!” laughs McElhinney. “I don’t always watch everything that I’m involved in, but I will watch this because I liked the series and I enjoyed doing it. I’m looking forward to seeing how it all comes together.”

And so are we – as well as finding out what this late-blooming star gets up to next.