Jason Merrells on why he couldn't resist returning as Waterloo Road's Jack Rimmer

Jason Merrells couldn’t be happier - after 17 years, the TV favourite is reprising his iconic role as Jack Rimmer in BBC1 school drama Waterloo Road.

"Jack’s my most favourite part I’ve played on TV - he’s so different to me in lots of ways yet always felt like the most complete character I’ve portrayed, so getting to revisit him was so natural," Jason says of the character, who was head teacher of the tough TV comprehensive for its first three series from 2006 to 2008, when Jack quit to take up a teaching job in Dubai.

Fast forward to now and Jack’s working as a counsellor for schools regulator Ofsted and, this week, crosses paths with Waterloo Road’s current head Dame Stella Drake (Lindsey Coulson), after she finally decides to seek mental health support following her recent attack by the parent of a student.

Stella reckons Jack could really help the kids of Waterloo Road - but will he want to return? Jason tells us more…

When you quit Waterloo Road in 2008, did you ever see yourself returning?

"No, I didn't ever expect to come back. When I left, I felt I'd done all I could do at Waterloo Road but that’s when everyone thought the show would run for four series… not 15! The original series has since become hugely popular on BBC iPlayer, then producers surprised me with this story last year. Although it’s a new school building, walking in and seeing all the stained glass decorations and the colour of the pupils’ uniforms, I felt a real sense of nostalgia. Playing Jack again has been like putting on a very familiar coat."

What brings Jack back to Waterloo Road?

"Initially, we learn that Jack remained in education for a long time after leaving Waterloo Road but then something happened, he needed to get help and, in doing so, he discovered he was quite good at helping others. Jack’s since become an Ofsted counsellor for teachers - and talking to new head Stella about her recent problems is how Jack comes back into the orbit of Waterloo Road. Jack’s role is quite significant in education now; teaching in inner city schools is a relentlessly difficult job, and it’s not getting any easier. Many teachers suffer from burnout, which is something it seems Jack knows a lot about…"

Stella warms to Jack and believes there might be a role for him at the school he was once head teacher of - but he's not keen. Why is that?

"Whatever’s happened to Jack, which is revealed further down the line, being back in a school and in that stressful environment is triggering. Although he’s still in education, he hasn’t worked in a school for years, so he’s nervous but also really connects with Stella. As head teachers, they’re very different yet similar in the way they think about the job and the vocation. That chimes with them both."

What’s it been like working with Lindsey Coulson, who plays Stella? And what more can you tell us about how their relationship develops?

"Years ago, I worked with Lindsey in Clocking Off, the brilliant BBC drama written by Paul Abbott, so I’ve always thought she was a cracking actor and it was lovely to hear she was playing Stella. Filming our scenes, we just clicked, and that mirrors just how Jack and Stella feel about each other - even though Stella is much more on point in terms of what a head teacher needs to be in the modern world, she also has anxiety and sees a strength in Jack; a flawed strength, but a strength nonetheless, that she can lean on. And he too leans on her."

What is it about Jack’s interaction with pupil-turned-caretaker-turned-teacher Donte Charles (Adam Thomas) that makes him change his mind about returning to Waterloo Road?

"Donte started out as the naughty kid that everyone - staff and pupils - loved but he had a difficult family life and often got into trouble. Because Jack had quite a troubled childhood, too, he saw a lot of himself in Donte, and was always rooting for him to do better. So when Jack sees Donte’s now a teacher, he's hugely moved by it - as is Donte as he remembers that, despite their run-ins, Jack was always on his side. I enjoy my scenes with Adam - I worked with him for a few years on Emmerdale [Jason played businessman Declan Macey from 2010 to 2014]. He’s a great guy and a fantastic actor."

Back when Jack was head, he had an affair with French teacher Steph Haydock (Denise Welch), came into conflict with disruptive pupil Lewis Seddon (Craig Fitzpatrick) and held much-loved character Izzie Redpath (Jill Halfpenny) in his arms as she died after being stabbed. Would Jack want to be head again?

"I think there's a part of Jack that would like to be head teacher again - and another part of him that would run a mile! So while he still has the desire and the ability in his bones, things have changed; he can't wrestle with students in the corridor or punch anyone that comes to the school gates looking for trouble like he used to!"

Can you confirm whether Jack’s going to be in Series 16 and, if so, what can you tease about the storyline?

"Yes, I am in the next series and all I’ll say is, whatever demons caused Jack to leave teaching come roaring back; we see Jack wrestling with them again and it's quite dramatic. It's a great story that coincides with the introduction of another teacher who’s initially Jack’s friend… then not so much! To find out more you’ll have to stay tuned…"

Waterloo Road continues Tuesdays at 9pm on BBC1.