Sheila Bridge is taking Year 10 assembly at Lutterworth grammar school in Leicestershire. It’s a challenge: Year 11 is using the hall, which means that Ms Bridge is fighting the acoustics and lack of ambience of a draughty gymnasium.

Assembly brought to a close, Ms Bridge oversees the tidying away of chairs. Elsewhere, Elaine Warden is taking a cover lesson. She knows the pupils, who listen quietly as she sets the work. When someone needs assistance Ms Warden is happy to help. So far, so normal. Except that neither woman is employed as a teacher; both are members of the school’s support staff. Ms Bridge is a year tutor, sharing responsibility for 638 young people with year head Peter Crossley. Ms Warden is a lesson supervisor, employed to cover for absent staff.

“The average supply costs pound;160 a day,” says assistant principal Vicky Bishop. “I’ve walked in on some where they’ve been reading novels. They are variable in quality. In my opinion, our supervisors do a better job.”

Lutterworth - a 14-18 non-selective upper school with almost 2,000 pupils - has spent the past 18 months using support staff in the ways the Government hopes will ease teachers’ workloads. But the National Union of Teachers is concerned about the use of unqualified staff in the classroom. The union has made clear to the Government its opposition to assistants acting as teachers and is currently canvassing its members on the issue.

Chris Henstock, head of Lutterworth, believes the NUT should rethink its stance. “The job of a teacher is much more complicated than simply standing in front of a class of children,” he says. “The average cover or supply teacher does little more than transmit to the students what another teacher has stipulated they should do. Teachers are over-qualified for that task.”

There are, he believes, real benefits in employing specialists to ease the burden on teachers. “All secondary schools would benefit from a Sheila Bridge. They’d benefit from reflecting on whether teachers are the best people to deliver front-line pastoral care.”

Ms Bridge spends her day dealing with pastoral problems, ranging from the aftermath of a fight between two Year 10 students to administering TLC to a pupil who’s finding school a bit daunting. She liaises with the school’s educational welfare officer, sees parents, handles phone enquiries and has a firm word with a boy who has broken the school’s rules on mobile phones. “The issues are as varied as the 638 kids we’re responsible for,” she says. “The intention is that I handle the day-to-day issues as they arise. If you deal with something at the very first moment, you can have an effect;you can change things so they don’t become a bigger issue.”

Do the students treat her differently from the teaching staff? “I hardly ever see poor behaviour in this office,” she says. “In here, they are properly respectful.” This may be because Ms Bridge is a trained teacher, although she insists this is not crucial to her role. “I’m qualified,” she says. “I worked in comprehensive schools for four years.”

But she’s had a variety of jobs since, and it was the one-to-one pastoral role that attracted her to her current position. “It would be very challenging for someone to do this without a teaching qualification,” she says. “But it’s not impossible. It’s experience that matters; experience of how schools operate.”

Neither of the school’s two classroom supervisors is qualified, but both would like to be. “They both hope to be teachers. One has a degree, and eventually we hope to place them on the graduate teacher programme,” says Vicky Bishop.

There was no shortage of applicants and the school has recently taken on a third supervisor. “Say you enjoy working with young people,” argues Ms Bishop. “You start at half past eight, go home at ten past three - end of story. For a lot of people, that makes for an attractive job.”

In return, the school staff get to keep their precious free periods and, if they have to be out of school, they know that their classes are in good hands. “Initially, staff didn’t want these people to do anything but supervise. The work had to be set by the head of department,” recalls Ms Bishop. “But that soon changed. The role has grown, they take far more responsibility. Increasingly, they set the work.”

She rejects the notion that this invades the province of the qualified teacher. “When people do cover, they’re not teaching. There’s no responsibility for preparing lessons, or marking, or recording pupil progress. This isn’t teaching.”

But it does allow teachers to get on with teaching their classes, just as Sheila Bridge’s work frees senior pastoral staff for other things. “I used to run a much smaller school,” says Chris Henstock, “and I wish I’d thought of this earlier.”