Robert Croft says he has seen the best of times and the worst of times overseas. He left these shores in 1989 to teach in Papua New Guinea, then ran an education agency responsible for 22 schools. He has since been head of an international school in Norway, and deputy head of Kings College, Madrid, one of eight British public schools on mainland Europe.

Despite his experience, four years ago when he took a job as head of a school in Nigeria, things went badly wrong. His brief was to set up a new British secondary school. But when building began, he was in for a shock.

“Everything was going fineI The next thing I knew all the workers had been rounded up by people with machine guns and army fatigues and taken off to the local prison.”

Mr Croft discovered there was a dispute over whether the school had permission to build.

“I was less than happy when I found that in purely legal terms, I could be sentenced to two periods of six months in prison in Lagos. Certainly, under the wording I saw, the titles headmaster and proprietor were almost synonymous.

“And Nigerian prisons! I’d seen the outside of one but I didn’t really want to be inside. I caught the first plane out with my wife.”

Today Mr Croft, 48, runs an independent school in trouble-free Northumberland. His experiences in Nigeria, although extreme, are a cautionary tale for anyone considering working overseas.

“It can be an incredibly rewarding experience,” he says. “But you have to be very careful - there are still hidden dangers.”

In recent months the Staffroom section of The TES website has had many messages from teachers relating unfortunate experiences abroad. Complaints include not getting paid, poor or shared accommodation, and a school that changed the job specification after a teacher had accepted the post. In one case, a teacher says he was fired because his wife was pregnant.

So how do you avoid the pitfalls? A good starting point is to apply through an agency. The biggest is the European Council of International Schools (ECIS), a non-profit-making organisation serving more than 570 schools. They can vary enormously. Some have up to 6,000 students; others fewer than 40. Typically, they cover 50 or 60 different nationalities.

Most are independently owned and managed, though some are embassy-sponsored, have government links or are part of a state school.

And many of the students are “third-culture children”, who have lived in a variety of different countries for most of their lives.

Agencies carefully vet the schools they accredit. For example, ECIS has strict criteria and visits its schools to ensure high standards. It also has ethical guidelines governing recruitment and employment.

According to Gabbitas, a long-established international recruitment firm, one common misunderstanding is that schools abroad are prepared to accept lower qualifications and poor experience to attract British teachers. In fact standards in overseas schools are as high if not higher.

And the jobs market is very competitive. Interviews can vary from a telephone chat to a long session in front of a panel. Most worthwhile employers want to meet candidates, although heads will not always have the time to come to the UK. You should take the opportunity to find out as much as possible about the post, the school and the country.

Be suspicious if you’re offered a job that greatly exceeds your expectations in status and seniority.

“There have been very many cases where golden promises have not been fulfilled, or have proved to be the gloss on a completely unsatisfactory professional situation in other respects,” says the company. “We have found very, very few who deliberately set out to hoodwink staff or to maltreat them in any way.

“However, quite a few have rather different views from those prevalent in Britain as to what constitutes reasonable conditions. We do not deal with institutes of this type. Our advice to any teacher is to look very carefully at the conditions offered.”

Another UK-based organisation that recruits for schools abroad is World-wide Education Service. It stresses that you have to ask the right questions. Teachers abroad can often find themselves in difficulty because of misunderstanding - interviewers may not speak English as their first language. What is understood by you at interview may turn out to be the different by the time you have flown out to take the post.

“People need to be very clear who they are working for,” says Therina Mulder-Reynolds, director of World-wide Education Service. “Is it a trust with governors as we recognise and know them? What are the terms and conditions of service? And, if it’s a new project, what are the financial liabilities?”

“It’s good to know who your predecessor was or somebody else you can make contact with, although remember that not everyone leaves a post harmoniously.”

Next term: the ex-pat lifestyle Gabbitas www.teacher-recruitment.co.uk ECIS www.ecis.org World-wide Education Service www.wesworldwide.com

EIGHT THINGS TO REMEMBER WHEN APPLYING

* Applications procedures are similar to UK posts, although you may be asked to provide photographs, copies of degrees or other documentation.

* Try to ensure that you give as much information as possible. Bear in mind that English may not be your interviewer’s first language.

* Do your homework thoroughly on the country. Make sure the place and its culture is right for you.

* At interview, misunderstandings can arise - for example, many non-UK employers do not see a distinction between primary and secondary teaching.

* Ask as much as you can about the school: Is it privately owned? Is it a charity? Does it have board of directors? Is it a profit-making organisation? Are the profits ploughed back into the school?

* If they make you an offer, ensure you receive a letter of appointment setting out the main terms. A formal contract is not usually available initially as it has to be prepared in a legal fashion in the country of origin.

* Satisfy yourself on pay and conditions before accepting. Take into account the country’s economic climate and its exchange rate.

* Don’t accept a post too impulsively. Occasionally employers take legal action and you could find yourself liable for costs in replacing you.