What drives a teacher into stress overload? For Roger Brind, head of Trelai Primary School on the Ely estate in Cardiff, little things emerge from the morass. He describes watching ice melt in parallel tracks on the playground at his 1950s school where pipes from the boiler house run underground to the main school building. Seeing Trelai’s budget evaporate before his eyes was just one of a multitude of travails he has faced over the past 19 years as Trelai’s head. “We had some serious problems that I certainly couldn’t see any answer to,” he says. “Socio-economic issues, legislation over the past 15 years - much of which hasn’t considered the starting point schools were at - an abominable building...”

Just before Christmas last year, 53-year-old Mr Brind went off sick, on doctor’s orders, suffering from high blood pressure and nervous exhaustion. No surprises there - heads and teachers up and down the country are being stretchered out of schools, and Trelai serves an especially deprived community, where 90 per cent of children are entitled to free school meals and 48 per cent are on the special needs register.

The school also has a unit for children with emotional and behavioural difficulties, and another for youngsters with moderate learning difficulties. Roger Brind has twice been faced with parents wielding guns, and another time he was threatened with a knife. There is constant interaction with social services. “All the things people in the past would have gone to church for, they now come to schools for,” he says.

But what is perhaps unexpected is that Mr Brind is back in school, sitting in his office in a blue shirt and a flowery tie, with a card on the board behind him reading “Keep on smiling”. He has been rejuvenated by a new regime: he goes to the gym twice a week, works only 10 hours a day and plans to retire at 60. Mr Brind has also resigned from five of the seven LEA committees on which he used to sit, and has instead given himself a small teaching timetable, because, he says: “I love teaching. I get a great release through it.”

Systems in the school for delegating responsibilities are now strictly adhered to. “I haven’t had a child put outside my door for bad behaviour yet this term, because I won’t have it any more,” he says.

It sounds suspiciously easy: simplify and be free. But Roger Brind’s route back from the brink has involved changes in the whole school community which have been anything but easy.

Early last year, he answered a small ad in The TES from a BBC team making a film about the work of the Tavistock Clinic in London, the country’s leading NHS centre for psychotherapy. They were looking for a headteacher to take part in a programme about managing stress and change in the workplace - with the help of Dr Anton Obholzer, a psychiatrist and expert in organisational analysis. What ensued was not just help for Roger Brind, but some uncomfortable adjustments to the status quo for the whole of the senior management team.

The Tavistock Clinic has 120 professional staff and an annual average of nearly 50,000 attendances. Individuals and families can be referred for many reasons, including bereavement, trauma, depression or family problems. Psychotherapy is a process which tackles mental distress not with drugs but with observation and thought: applied to organisations, it is termed “organisational analysis”.

But while therapy and counselling have entered the mainstream of personal life, with individual teachers using counsellors or telephone helplines to help them cope with stress, the language and vantage points of psychotherapy have stayed outside the school gates until now.

The resulting film, Talking Cure will be shown on BBC2 next week. It provides a fascinating glimpse of how teachers can reduce stress collectively by opening up discussions in the staffroom.

It begins innocuously with lingering shots of Trelai’s stained concrete walls and rainwater standing on the tarmac under a pearly sky. The bell rings for the start of the school day and Roger Brind greets pupils in Welsh. “Bor Da,” he says. “Bor Da.”

Apart from the Welsh it could be any hard-pressed school on any bleak estate. But what the consultant from the Tavistock found here was “an extraordinarily complex and difficult situation: The school is attempting to do a great deal more than just educate the children,” he says. “They are providing emotional stability, physical care - a reparative socio-educational system.”

In conversation with Anton Obholzer at the Tavistock Clinic in London, Roger Brind identifies the gulf between his ideals and ambitions and the reality of what he can achieve at Trelai. He describes the way teachers grew trees from seed, and when they grew too large for the foyer planted them out in the playground. Within days, all the trees had been vandalised, torn up by the roots.

As well as having individual sessions with Roger Brind, Anton Obholzer came to Trelai four or five times for meetings with the senior management team. He appears on film trudging through the landscape in a hat and greatcoat. The Ely estate is a very long way from the Tavistock in Hampstead, and even further from South Africa, where Dr Obholzer comes from.

Although Roger Brind is at the end of his tether, Dr Obholzer says his is not an individual problem. “It’s partly a personal matter, but many things need to be dealt with on an organisational basis, so that people share the issues and what one might do with them.”

The group conversations in the staffroom in the presence of Dr Obholzer, make riveting viewing. When teachers tell the consultant that they save being ill for the holidays, that they find it difficult to say “no”, that they are constantly pulled in different directions in a desire to do their best for all the children, he asks if the problem is “too many dedicated teachers”. This prompts nervous laughter.

“Is the unspoken agenda,” asks Anton Obholzer, “that nothing can be done? That it’s an impossible situation that teachers can’t do anything about, that the head can’t do anything about, the Government doesn’t do anything about, the consultant from the Tavistock can’t do anything about, so we can go home and be reassured that there’s nothing to be done and we can all carry on as before?” More laughter.

Anton Obholzer says the unsayable: wondering out loud whether Roger might be part of the problem. “He’s so proud of the school and has worked so long and so hard, that one feels one has to work to maximum capacity.” And he raises the issue of After Roger. “He’s going to leave sometime. Or he might get ill. How would the teachers function in his absence?” Roger listens with his hand over his mouth as staff mumble that that is something they don’t want to think about.

Practitioners at the Tavistock believe that the workplace can be an emotional minefield, and that we often invest as much in it as we do into family life. This appears to be borne out by events at Trelai. In the second meeting between Dr Obholzer and the senior management team, Roger Brind is absent, called away unexpectedly to a meeting. It emerges that this absence is characteristic, and a source of frustration to staff. This has been tackled humorously - the staffroom joke is that ROA stands not for Record of Achievement but for Roger’s Out Again.

On film, staff admit that they mean what they say in jest: that the head is making impossible demands on them and is not around enough, leaving them even more over-stretched than they might otherwise be. He also likes the school to keep up with the latest educational developments. “What you have is the responsibility of running the place a lot of the time without the status and other things that go with it,” Anton Obholzer tells deputy head Dianne Nicholls.

When Roger Brind returns, true to the style of psychotherapy, Anton Obholzer “feeds back” the staffroom conversation to Roger and asks him what he has to say for himself.

As a senior head and a champion of marginalised children and the schools that serve them, at the time Roger Brind believed his role in the wider sphere was paramount. “Unless you are prepared to play your part in the consultation process, there is no voice for schools like ours,” he says, the lines on his face deeper than ever.

Staff listen in silence as he then says: “I just can’t carry on like this. The pressures on me are too great.” The camera returns once again to the silvery skies over cell block Trelai. Thunder rumbles.

The Tavistock techniques don’t provide easy answers. Roger Brind went off sick the following day, before the end of the Christmas term. Anton Obholzer admitted to being “vaguely panicked” by this turn of events, but preferred to view it as “movement in the logjam”. Staff who had been in on the last meeting felt guilty. “I think we all felt bad,” says deputy head Dianne Nicholls. “We haven’t seen him since.”

Three months later, he was still away from school and Dianne Nicholls was standing at the school gates in a black chimney pot hat with a shawl round her shoulders, welcoming Ofsted into the school on St David’s Day. The inspection went well.

Twice Roger Brind drove up to the school gates intending to pay a visit to his colleagues and then drove away, unable to face entering the building. “I did wonder if I would ever work in here again,” he says.

But in June this year he came back. Helped not just by interaction with Dr Obholzer but also by his dealings with the county medical officer - a psychology specialist - and his GP, Roger Brind has learned that he must look after himself as well as others. “I’ve told myself I’ve got to have a work pattern, and work hours, and stick with them,” he says. “I’m far more effective and more efficient.”

Members of the senior management team conduct themselves differently too now. Lesley Leckie, 40, is head of the infant department and acting deputy head since Dianne Nicholls’ retirement. “We’re very loyal to each other, and although we feel we’re very open, the film brought out that we need to be even more open,” she says.

“Professionally, it has been good for us. We try to make sure now that there’s never any secrecy and that nobody’s left out.” Mrs Leckie, whose husband is a primary head on long-term sick leave due to stress, says the delegating habit is spreading. “You might moan about it, but being delegated to is developing us. We’re delegating more too.”

Roger Brind and the staff at Trelai have exposed the stresses and tensions that occur in all schools. “There is a desperate need for honesty in the education system,” he says. “The problems I’ve had and we’ve had in this school have been solved.”

For Anton Obholzer, the process at Trelai school, he says, was one of “attempting to help them out of a passive, dependent state of mind into thinking about what could be done by them, for themselves. You’re making a thinking space about the pressures and how they can be addressed.”

Dr Obholzer, who has worked extensively with organisations in both the public and private sectors, says that similar issues crop up across the public sector whether in schools, prisons or social services departments.

While few schools will be able to afford the Tavistock Consultancy Service public sector fee of pound;140 per hour, Dr Obholzer suggests that just the presence of an outside consultant at staff meetings, such as an educational psychologist, can be helpful.

“It makes sense to realise,” says Dr Obholzer, “that there are substantial overt and hidden costs for poor functioning of staff in all organisations, including schools.”

Much at the school has not changed. In a display in the lobby of the pupil’s thoughts on the millennium, one child has written of her hopes “that we will have a new school and it will have elevators and no cracks or holes in the roof. I would like to have an inside swimming pool with showers.” But Roger Brind is sanguine. “What I learned more than anything was to let go of things I could do nothing about,” he says.

Talking Cure is on BBC2 at 9.50-10.30pm, on November 16.The Tavistock Consultancy Service may also be able to makerecommendations about regional or independent consultants.Tel: 0171 447 3737.