Martin Blain managed to land the job he wanted within days of returning to Britain from a two-year stint in Eritrea.

A mathematician who had gone to the impoverished east African state with Voluntary Service Overseas, Mr Blain accepts picking up his career where he had left off was relatively easy, partly because of the United Kingdom’s shortage of maths teachers. It also helped that VSO, which offers job search and other support to returning volunteers, faxed his application from its office in the Eritrean capital, Asmara, to Queen Elizabeth’s, the north London boys’ school where he now teaches.

In Nakfa, the remote town where Mr Blain taught, he and three other VSO teachers were paid the same as their Eritrean colleagues. They also lived in the same conditions as local people, doing without running water and other comforts taken for granted in the West.

The personal skills he picked up as part of a community of goat farmers have, he says, made him a better teacher. But while the panel that appointed him to his present job seemed to agree, not all teachers returning from a spell abroad come across such enlightened attitudes.

Peter Gummer, a director of Gabbitas Educational Consultants, which recruits teachers to overseas schools, says some heads believe teachers working abroad have been doing nothing but sunning themselves under palm trees. They do not realise that many British schools abroad follow the national curriculum and have to meet the often high expectations of expatriate parents who are paying hefty fees for their children’s education.

But even less blinkered employers can be reluctant to appoint someone fresh from abroad to a promoted post, and returning teachers often have to start again at the bottom of the career ladder. They may also be financially worse off than if they had stayed home because overseas service - except in Ministry of Defence schools - is not automatically recognised for pay purposes.

“Most people coming back from overseas are a good bet, but they don’t always find it easy and it’s not only that the schools don’t want them,” says Peter Gummer. “When you have been a fairly big fish in a small pond overseas, and lived a rather attractive life, settling back in can be difficult.”

Some teachers never settle back permanently but become career expatriates. David Phillips, a primary school teacher, caught the travel bug in 1987, when he went to teach in a state school in the Bahamas. The school was poorly resourced and the work challenging, but Mr Phillips enjoyed the freedom he had to put his ideas into practice. The same was true of the five years he later spent in a private international school in Saudi Arabia.

Contrasting this experience with working in the UK, he says: “It was real teaching - teaching what needs to be taught and not worrying about covering your back all the time and having to produce evidence of what you’ve done every minute of the day.”

Now back in the UK, where he has a temporary job in an East Sussex primary school, Mr Phillips will be returning to the Middle East in September, when he takes up a job in a British school in Kuwait. He hopes to spend the rest of his career abroad.

Information about Voluntary Service Overseas is available from the VSO enquiries unit on 0181 780 7500