Thankfully, such cases are rare. Unions are probably better known for test boycotts or wage disputes than for compensation settlements.
Nevertheless, the legal help and advice of a union, free to all members, can prove invaluable.
Union membership is like an insurance policy - most of the time you pay out an annual sum and nothing seems to happen. But, as countless members can testify, it's better to be safe than sorry.
Although problems and pitfalls of the teaching profession may not be as obvious as those of house or car ownership, accidents do happen and a good union is one that can help its members when they get in a scrape. All the teaching unions employ solicitors whose job it is to give legal advice to their members and, if the matter needs pursuing, to represent them in tribunals or courts.
A look at some of the cases recently resolved by the teaching unions illustrates the variety of situations in which unions can help: The union successfully appealed to the Academic Board Review Committee on behalf of a newly qualified teacher whose college had refused to award her degree. The degree was confirmed and the teacher kept her job.
A 46-year old teacher who slipped and fell, injuring her back and forcing her to take ill health retirement, received Pounds 74,000 compensation after it emerged that the floor of the school hall had been too highly polished.
A pupil told his father that he had been told to "wring necks of chickens" in science classes. His father told a local paper and the story was later published in a national tabloid. The teacher won libel damages of Pounds 18,000.
After changes to the School Teachers Pay and Conditions Document in September 1993, a primary school teacher discovered that she had not been paid in accordance with her experience. The union secured back payment of some Pounds 5,000 from the local education authority.
The union backed a member who had been suspended and accused of assault after attempting to break up a fight between pupils. Charges were dropped and the teacher was reinstated.
A language support service teacher was awarded Pounds 25,000 damages after injuring her back while transporting equipment, forcing her to retire from work.
Teachers at a convent school, all of whom had more than 12 years' experience, found their jobs under threat when the school was taken over by a parents' trust.
Union intervention secured their jobs and employment rights.
For teachers who decide to join a union, the question is: which one? There are four main unions in England and Wales competing for the support of newly qualified teachers - the National Union of Teachers (NUT), The National Association of Schoolmasters Union of Women Teachers (NASUWT), the Professional Association of Teachers (PAT) and the Association of Teachers and Lecturers, (ATL).
The first two are affiliated to the TUC, while the PAT and ATL are independent unions. In addition to their role as representative bodies, they all offer a wide range of financial services such as home and car insurance, mortgages, and credit cards as well as discounts on travel and holidays. Subscriptions paid by direct debit are usually cheaper.
NUT, Hamilton House, Mabledon Place, London WC1H 9BD, Tel: 071 388 6191.
Membership: 220,000. Combative and campaigning, the NUT is the country's oldest and biggest teaching union. Recently backed down in its test boycott, it is still opposed to school league tables. "The union aims for a high quality education system, based upon equality of opportunity, leading to maximum achievement for all pupils."
NQT benefits: Free first term's membership. Reduced subscription rates for first two years. Campaigning for a reduced workload for NQTs of 80 per cent during first year of service.
Publications: The Teacher, published eight times a year, free to members. Twice yearly Education Review, Pounds 5 annual subscription.
NASUWT, Hillscourt Education Centre, Rose Hill, Rednal, Birmingham B45 8RS Tel: 021 453 6150.
Membership: 207,000. "The career teachers' organisation" and "The only teachers' union to represent the common interests of all teachers."
NQT benefits: Free first term's membership. Half price for first two years.
"Find a job" information pack and guide with advice on CV, interviews and applications. Claims "more NQTs join NASUWT than any other teacher's association".
Publications: Career Teacher, 10 issues a year, and Teaching Today a termly in-depth journal.
PAT, 2 St James' Court, Friar Gate, Derby DE1 1BT, Tel: 0332 372337.
Membership: 40,000 Established in 1970 by two Essex teachers dismayed by the effect of strike action in schools. Cardinal rule: "members shall not go on strike in any circumstances" and motto: "Children first."
It says "action which damages the educational chances of young people also damages the reputation and standing of teachers in the community and society at large".
NQT benefits: Free first-term membership. Reduced rate for first two years.
Publications: Professional Teacher five times a year. Range of advice booklets.
ATL, 7 Northumberland Street, London WC2N 5DA, Tel: 071 930 6441, Membership: 159,000.
Until 1993, the ATL was the Assistant Masters and Mistresses Association (AMMA), which dated back to 1894.
"A grassroots organisation. . .to promote the cause of education. . . to protect and improve the status of teachers and... to render legal advice and assistance."
NQT benefits: Special offers on new members' subscriptions.
Publications: Report magazine, eight times a year, free to all members. Update, a regular newsheet, usually monthly.
Educational Institute of Scotland (EIS), 46 Moray Place, Edinburgh, EH3 6BH, Tel: 031 225 6244.
Membership:48,600 Represents 80 per cent of teachers and lecturers in Scotland.
Publications: Scottish Educational Journal and occasional bulletins Scottish Secondary Teachers' Association (SSTA), Dundas Street, Edinburgh EH3 6QG, Tel: 031 556 5919.
Membership:7,100 Only union devoted exclusively to secondary teachers. Services include access to independent financial brokers.
Publications: The Secondary Teacher quarterly and bulletin to members six times a year.