The photocopied letter pinned to the staffroom noticeboard at the inner-London comprehensive looks unremarkable. But the story it reveals, on two pages of A4, is shocking. The parents of a Year 8 girl - not yet a teenager - are being formally told of the school’s intention to permanently exclude her because she has threatened a teacher with a knife.

Incidents such as these unite staffrooms like nothing else. Permanent exclusion is the only option. But schools have to follow strict procedures to make an exclusion stick. This letter goes to great lengths to outline the parents’ rights: to attend and be represented at the governors’ meeting this month that will consider the exclusion; to see their daughter’s school record; and to make the case, if appropriate, that the girl’s behaviour resulted from a disability of some sort. But it is almost unheard of for cases like this to end with a school re-admitting the pupil in question.

However, teachers tread this path with mixed feelings because they know that provisions for permanently excluded teenagers are, at best, patchy and can sometimes lead to the individual getting into more trouble and falling further behind in their education.

The deputy head at another London school, which recently permanently excluded a Year 8 boy for brandishing a penknife in a playground fight, spoke of the anguish she felt at the time. “We knew he’d be going to the local pupil referral unit and would probably go from bad to worse. It played on my mind. I felt we were damning him to a life of ruin at a very early age. But you have to do it for the greater good of the rest of the pupils and your school.”

Permanent exclusion is often the culmination of an extended period of worsening behaviour, attracting punishments of increasing severity, including a series of fixed-period exclusions of anything from one day to a fortnight. But schools are becoming increasingly aware of the limitations of these measures. Many pupils treat them as a badge of honour - relishing the time out of school, which is often spent strutting around shopping centres or learning the finer arts of daytime burglary.

This is why some schools are now trying to devise more ways of dealing with bad behaviour in-house. One example is Pool Business and Enterprise College, an 11-16 comprehensive serving the towns of Cambourne and Redruth in Cornwall. Four years ago, fixed-period exclusions were running at a rate of more than 800 days a year - in a school with only 800 pupils, an average of one day for every pupil. This year, since last September, there have been only nine.

The key component is the strict use of an inclusion room, where pupils whose behaviour would have warranted an exclusion now spend their time. The room has seven screened-off desks, each facing the wall. The pupil’s day begins with a meeting with a senior teacher and their parents, to discuss the behaviour that has brought them there. Work is set for them to do, in silence, and they are allowed no contact with friends, with breaks and lunch taken in isolation. And at 2.55pm, when the rest of the school can be heard making their way home, the pupils in the inclusion room know they won’t be let out until 5pm.

The room is run by Ben Tame, a member of Pool’s support staff, who is now inclusion manager. He says it has transformed the school and drawn a line in the sand regarding what is expected in terms of behaviour and values.

“Work completed in the unit has genuine value,” he says. “Away from distractions and peer pressure to act up, many of the pupils are surprised at how much they get done.”

For Jeremy Rowe, deputy head, the success has further underlined the weaknesses of the fixed-period exclusion system. “Fixed-period exclusions just don’t work and it’s time we all admitted it,” he says.

And he is dismissive of the recent change in the law making parents responsible for supervising their children during the first five days of exclusion. “The excluded pupils usually come from the very homes where parents can’t enforce discipline in the first place.”

His views are largely echoed by Mike Hall, assistant head in charge of inclusion at The Canterbury High School, a mixed comprehensive serving some of the more disadvantaged areas of the cathedral city.

“Fixed-period exclusions are a total waste of time, other than to send a message to other kids. But we can’t allow learning to be disrupted so we have to use them sometimes.”

To try to channel potential troublemakers away from disruptive behaviour, the school employs two full-time youth workers, who run courses such as the ASDAN Personal Effectiveness awards and outdoor activities - all designed to maintain engagement among less academically inclined pupils. The school also has links with a number of outside organisations in the public and voluntary sectors, to which difficult pupils are referred for help.

“All of this is definitely reducing the number of pupils who will get into trouble and face exclusion,” says Mike.

The Advisory Centre for Education, a charity that receives more than 2,000 calls a year from parents wanting to challenge exclusions, also suggests that many are unnecessary. “The feeling we get from a lot of our calls is that some exclusions are a knee-jerk overreaction to relatively minor incidents, which could be dealt with by other methods,” says a spokesman.

Another example of alternative methods, at Aveley School, an 11-16 comprehensive in Essex, has had marked success. The school has four non-teaching staff, collectively called the supportive intervention team, who patrol the corridors and deal with all cases of pupils not in classrooms. “If a teacher has asked a pupil to leave a classroom for bad behaviour, they’ll be picked up within five minutes by the team,” says Huw Derrick, deputy head. “They will either counsel the pupil and get them back into class quickly, or take them away for a more substantial discussion.”

The policy has been so successful that the team, initially given an inclusion room to work from, has now been allocated a classroom in which it runs proactive sessions to try to head off bad behaviour.

“It’s fantastically successful and definitely responsible for reducing our exclusions,” says Huw. “Before, we were nearly the worst school in the area on exclusions. Now we’re in the middle of the pack. I’m convinced it contributed to our successful Ofsted inspection in January, when behaviour didn’t attract a single negative comment.”

EXCLUSION FACT FILE

Latest figures, for the school year 200405, show that 220,840 pupils were excluded from schools in England for a total of 389,560 fixed periods: a rise of more than 10 per cent on the previous year.

In the same year, there were 9,440 permanent exclusions, down four per cent on the previous year.

The most common causes were: persistent disruptive behaviour (27 per cent); verbal abuse or threatening behaviour against a member of staff (23 per cent); and assaulting another pupil (21 per cent).

WHAT THE UNIONS SAY

Chris Keates, general secretary of NASUWT: “I am all for schools choosing what works best for them, but sometimes an isolation unit doesn’t send the right message to the rest of the school community. Used properly, fixed-term exclusions can be very effective.”

The National Union of Teachers: “Sometimes a fixed-term exclusion is the only way to protect the education of the 29 other well-behaved pupils in a class, and not all schools have the space or resources to provide an inclusion room on site.”