There are worse letters to open: “We regret to inform you that your contract has been terminated with immediate effect.” You could win a weekend away with Gordon Ramsay, but “You’re fired” has to be up there in the top five phrases people would rather not hear.

Employers can legally dispense with your services in three ways. Redundancy is the most common: that’s where you are surplus to requirements. Then there’s disciplinary action after an employee has breached workplace rules and regulations. And, finally, there’s capability, where someone is judged not to be up to the job they’re hired for.

Teachers undergoing capability procedures face a 24-week assessment, which can be cut to four weeks if pupils are climbing the walls. Governors must follow proper procedures: they can’t fire you just because your classroom display isn’t triple-mounted. Most schools use the model procedures published by the Department for Education and Skills.

Penny Wheeler’s case is typical. A bout of depression led to problems at work: lesson preparation was skimped, marking left undone and her attendance and punctuality suffered. The experienced Midlands primary teacher was first faced with her head’s concerns before a formal interview set the capability process in action. She was given clear targets to achieve in her attendance, record-keeping and lesson preparation - and a written warning about the perils of failing to meet them.

The school offered support: regular monitoring and a workload assessment.

Her local education authority offered counselling and her union supported her throughout. At the 20-week cut-off point, it was decided her work had improved and the procedures were dropped. Had she failed, the school would have started a final four-week assessment that could have led to dismissal “This was a clear case of a good teacher going though a temporary crisis,” says her union regional officer. But that isn’t always the case. Where problems are more deep-seated, the union will represent you, but will not necessarily insist that you stay in the job.

“It’s in nobody’s interests that someone who is falling into capability procedures should remain in front of a class for too long,” says Graham Clayton, the NUT’s solicitor. “Most teachers know when they are failing.

The aim is to smooth their departure with decency and honour.”

Some people think that illness, mental or physical, will circumvent capability. But Mrs Wheeler’s depression didn’t prevent action against her.

The DfES procedures allow employers to proceed with evaluation meetings even if the employee is absent through illness.

“People think that illness will be a mitigating factor,” says one local authority personnel manager. “But fitness to teach is part of the capability assessment - and if the illness is sufficiently long-term or debilitating, then it could become the main reason for letting someone go.”

Capability is not a big issue in schools. One study found that heads had concerns about less than 2 per cent of teachers, which would equate to 5,000 people if extrapolated across the country. “It was never true to say, as Chris Woodhead did in the 1990s, that there were 15,000 incompetent teachers,” says Mr Clayton. “We deal with a very small number of cases.”

Last year’s figures show only 29 of the 3,000 teachers who went through capability procedures were dismissed.

Teachers who leave in a hurry do so for other reasons, such as misconduct.

But the situation is clouded in mystery because many facing such an investigation resign before they can be dismissed. Which may not be the best course of action.

One teacher told The TES how she had faced a bullying head for six years, during which time she was threatened with “informal” capability procedures before finally being accused of striking a pupil. “I was bullied by my head who failed me on all eight targets of my threshold application and eventually suspended me,” she says. “She told a colleague she believed I was stealing.”

“I decided to resign because of the effect on my health and family. That, apparently, was the wrong decision, because once I left there was no procedure for me to have my case heard.”

Graham Clayton of the NUT advises: “Teachers in this situation should ask the school’s governors to investigate by declaring a ‘grievance’.”

All schools should have grievance procedures. In most, a sub-committee of the governing body will hear the case, with the possibility of an appeal to a separate set of governors. In practice, governors often feel that they have an obligation to support the head, but it does at least offer teachers an opportunity to put forward their case. Proper grievance procedures are even more important today. Employment tribunals, where disputes between employees and employers are settled, now expect a dispute to have exhausted the grievance procedures before going to court.

But what happens when schools ignore such procedures? Davina Lingard says she was sacked this year because she had a civil wedding, contrary to the wishes of her Roman Catholic primary school in Cardiff. The school said there were legitimate and valid reasons for her dismissal. “Her contract wasn’t renewed,” headteacher Mike Flynn told reporters. “That’s not unusual.”

Which is true. But heads who use temporary contracts to manage short-term staffing may be flouting the law. “Fixed-term contract misuse happens too often,” says Mr Clayton. “Non-renewal of a fixed-term contract is a dismissal, and in this case the teacher could take her case to an employment tribunal.”

Tribunals cannot force employers to reinstate someone who has been dismissed. But they can award costs and damages. The rule is always the same: employees faced with dismissal should never walk, unless they wish to leave.

Some names and details have been changed to protect the identities of those involved

NEVER WALK THE PLANK

* Don’t be bullied into resigning.

* Always involve your union. If you are not in a union join one now.

* Do not attend meetings unrepresented. You are entitled to take a ‘friend’

into meetings.

* Ask to see written details of any accusation made against you.

* Launch grievance proceedings at any stage if you feel that proper procedures are not being followed.

* Keep a written diary detailing how your case is handled.