Playing The Part (BBC1, 8pm)

THE day before she’s due to become a teacher, actress Denise Welch is wishing she hadn’t agreed to go back to school. “I think I would rather be on that programme where you swap wives,” she says.

“Honestly, I’d rather sleep with Paul Daniels than do this tomorrow. Not a lot, but I would.”

And there are times during the week she teaches English at her old school in her home town of Consett, when you feel she longs to scream: “I’m a celebrity, get me out of here.” Bushtucker trials would be easy-peasy compared to teaching a class of teenagers.

This occasional series lets actors do the job of the character they play. Welch has been a landlady in Coronation Street and army wife in Soldier Soldier, but is currently in the classroom, in BBC1’s Waterloo Road, as flirtatious, but lousy French teacher, Steph.

So 34 years after leaving, she returns to her old secondary school, now a comprehensive known as Consett Community Sports College, to teach English for a week.

She’s part of the 50-strong teaching staff tutoring 700 pupils. Husband Tim Healy is more confident than she is.

“She’ll keep them in order anyway, just like she does in the house,” he suggests.

Welch wants them to like her, but also to respect her. Her first class comes as a shock. Using celebrity magazines in an effort to stimulate debate faces a wall of silence.

The class has never been so quiet.

Her next lesson gets off to a bad start when she can’t find the classroom. Good job she’s not teaching geography.

After the lesson, one pupils says she should be more strict. It’s coming to something when your students don’t think you’re harsh enough.

Of course, a show like this tells us as much about Welch as the pupils. She’s worried, for instance, about teaching the top GCSE class of 16-year-olds because “they’re quite bright”. She also has trouble keeping to lesson plans prepared by her colleagues.

After the first day, she’s found it “enjoyable, stressful, eye-opening and knackering”.

Class 11X6 is her biggest challenge and also, it turns out, her biggest success.

These are final-year students in the bottom set of English.

She asks them to find 20 good things about Consett. They go to the computer room to do their research, only they Google her, not Consett. They confront her about having a nervous breakdown (following post-natal depression) and her previous alcohol problems. Perhaps they respect her honesty in not telling them off, but explaining how people, and not just her, face up to such difficulties.

Their “proper” teacher, observing what’s going on, is amazed at seeing pupils actually taking an interest in their lessons. “They look like angels, they like her,” she says.

Welch the teacher is not behaving as well. She doesn’t take criticism delivered by the head of English for deviating from the lesson plan. “I just want to throw my toys out of the pram and go home,” says Welch.

IT gets worse. She has a crisis in the middle of a lesson and flees the classroom in tears, crying: “I don’t know how to teach this. No one has helped me, I’m an actress.”

Being late for school the following day, having failed to set her alarm and slept in, doesn’t help. The long hours and teaching a subject for which she’s not fully prepared is leaving her stressed out.

There are lighter moments. Like meeting a pupil who’s related to a boy, Tommy, she went out with when she was 16. But she’s embarrassed to realise this isn’t his son, but his grandson.

What does Welch learn from the experience?

The obvious thing is that teaching is nothing like acting. The classroom isn’t about the teacher, but the students, not about teaching, but about learning.

It’s a valuable insight into the teaching profession, but not, I suspect, a lot of help when she goes back to playing Steph.

She’ll continue to fail at French, but gain an honours degree in flirting.