It's the first lesson after morning break in one of the classrooms of the Alternative Learning Centre, a small school on the outskirts of Bradford, which takes in some of the most badly behaved teenagers from comprehensives in the area. At these desks, over the past few years, have sat some of the hardest cases in the city: teenagers with records of violence in school, long-term truants, girls involved in prostitution, and others afraid to go to school because of bullying.
But, despite the clientele, the atmosphere is calm. As the five students tap away at computers, on a project to design fire evacuation plans for their homes, there's no swearing, no disruption and no undercurrent of hostility towards the three teachers in the room.
The centre is run by a voluntary Christian charity called The Lighthouse Group, which has caught the eye of politicians of all persuasions for its success in dealing with one of the hardest nuts to crack in education: the growing body of pupils whose behaviour mainstream schools can't cope with.
On average, every term-time day in England, around 1,700 pupils are excluded from school, usually for between a day and a week. This may be triggered by a one-off event – swearing at a teacher or hitting another pupil – or by persistent classroom disruption.
Last year, the number of these temporary exclusions rose by 4 per cent, to more than a third of a million. But, surprisingly perhaps, when these figures were released earlier this summer, ministers applauded the rise, and linked it to a fall in the number of permanent expulsions, which were down 7 per cent to 8,680. The argument was made that the increase in temporary exclusions was evidence of schools using short, effective punishments to turn around poor behaviour.
But despite putting this positive gloss on one batch of statistics, ministers have demonstrated their wider dissatisfaction with the current system by announcing an overhaul of how excluded pupils are dealt with. In particular, they've signalled their preparedness to look to the private and voluntary sector for answers.
This chimes with a pledge from the Conservatives, who have advocated "a whole new relationship between state schools and those voluntary bodies and social enterprises with real expertise in turning around kids who get excluded".
This is where The Lighthouse Group comes in. Its centre in Bradford, together with smaller ones in London and Birmingham, are held up by the Tories as the way forward.
So what are the key ingredients of the group's approach? The first, according to chief executive Tim Morfin, is the fact that the organisation is not part of the established system.
"A lot of people we are working with have massive issues with school, and have parents who themselves despise the system," he explains. "We are rightly understood to be not school and not social services. However, we do work in partnership with them."
A second difference is that, unlike most local authority-run pupil referral units, The Lighthouse Group takes teenagers before matters at school have escalated to the stage where they've been permanently excluded. This allows them to attend the centre for two or three days a week and go to school for the rest of the time, perhaps returning to school full-time after a spell at The Lighthouse Group.
But perhaps the most important factor is what the students achieve at the centre. "By the time they come to us, they've missed the boat as far as qualifications are concerned," says Morfin. "But we offer them a second chance, by running a programme that will give them a qualification recognised outside."
That qualification is an Asdan award, recognised by the Qualifications and Curriculum Authority, and designed for teenagers turned off by the traditional diet of GCSEs served up by the vast majority of secondary school pupils.
In general, Asdan (Award Scheme Development and Accreditation Network) courses bring social and life skills to the fore, and embed elements of literacy and numeracy in projects that are rooted in the real world.
On the day of my visit, the The Lighthouse Group students were working on an Asdan unit called problem solving. Some were addressing how to get the fire brigade to assess the fire evacuation plans they'd been devising. Others were making plans to sell a music CD produced by The Lighthouse Group. Both were real projects, involving contact with the world outside.
As the teenagers looked online for phone numbers and wrote emails seeking help or information, it was noticeable that the adults in the room left them to their own devices, only occasionally intervening to encourage them to keep exploring and not be put off if one or other course of action came to nothing.
Adam Syrop, a team leader at The Lighthouse Group, says developing the ability to solve everyday problems is key to the students' progress in life.
"The students struggle with problem solving because they are so used to giving up when they can't deal with something," he explains. "But we don't lead them by the hand. They won't learn anything if we do that."
In another strand of the Asdan course, called working with others, the students, in twos or threes, were given a budget to buy, and plant out, new flower boxes on a patio outside the classroom. These are now in place and blooming.
It's the collaborative element of this, according to Syrop, that's of so much value. "This is when our students benefit the most, as they struggle with mainstream schools because they can't deal with authority or work with others." There are occasional eruptions of emotion, of course. During a group discussion I witnessed, one boy rushed out of the room protesting loudly at what he saw as intransigence from the others. But minutes later, he came back in without a fuss, and without adult intervention.
Despite the light touch approach, though, this is certainly not an institution without rules. Students have to earn their right to play computer games or pool during break times by working sensibly and productively during lessons. When one boy arrived late at the centre while I was there, he was told in no uncertain terms that he'd missed his chance for a morning cup of tea and should go straight to the classroom and have a drink of water.
Although none of this is revolutionary, or radically different from the approach of pupil referral units, The Lighthouse Group seems to have hit on a formula that works. Since its centres first opened nine years ago, 90 per cent of teenagers referred to them have gone on to further education or training after school-leaving age.
Morfin's aim is to see scores of centres open across the country. Three more – in Manchester, Nottingham and a second in London – are planned for the next 12 months.
But he doesn't pretend to offer a cheap solution. A school has to pay about £2,000 to place a single student in a Lighthouse Group centre for two or three days a week over a 12-week period. And that represents only part of the cost of the group's overall operation.
But pupil referral units or "sin bins" are anything but cheap. Local authorities spend tens of millions of pounds a year on "sin bins" , much of which is judged not to be working.
So both main political parties, rather than looking primarily at cost, appear to be searching for institutions that stand a sporting chance of bringing about lasting change in the lives of teenagers who've gone seriously off the rails.
And Morfin believes The Lighthouse Group provides the template for the future. "In the long term, work like ours is here to stay because we are uniquely placed to make a difference."
Sheri Leigh, 13, started attending The Lighthouse Group for two days a week at the beginning of the summer term.
"I've got anger issues. I don't fit in at school and get wound up easily. But here I get wound up less and I'm learning to control my anger and not to react to things so much.
"I've learnt how to do a bit more maths here and how to use computers better. I also like the problem solving.
"I enjoy it more here because I feel more welcomed, by the staff and the pupils. I'd like to come here full time."
Brandon, 14, is in his second 12-month spell at the The Lighthouse Group, attending two days a week.
"School sent me here for fighting, misbehaving and stuff. I like it here, because I like the teachers, the classroom and because it's not like school.
"There's a pool table, a Wii, an Xbox, and not as many lessons. I don't do anything in ICT lessons at school, but I do get my computer work done when I'm here.
"My dream is to be in the Army or to be a builder."