In the toilet of Leeds Tesco, Mamadou Sylla leant against a cubicle wall and cried. There was much for him to cry for: a lost country, an abandoned life, two children thousands of miles away, a scarred and damaged body. And the fact that after six years of running his own school, he was here, in the toilet of Leeds Tesco, crying when he should be scrubbing sinks.

Mr Sylla (pictured left) was forced to leave the Ivory Coast in 2007. After 12 years in education - six teaching French and six as headteacher - he had been appointed general secretary of the teachers’ wing of liberal opposition party RDR (Rally of the Republicans). Shortly afterwards, he was arrested.

“The government was trying to crush people and destroy the party,” he says. “Crush you and maybe kill you.”

He was kept in jail for about six weeks. He no longer talks about what went on there - “I don’t want to remember it” - but the scars covering his body serve as a permanent reminder.

He remembers very little of what happened after his release. The police attempted to trap him: they told him to come to a certain location because his brother was sick. But he knew that his brother was not ill and so refused to go with them. Later, he heard that a fellow ex-prisoner had been taken in by the same trick; the police had killed him.

“The only thing to do was run away,” Mr Sylla says. “I knew that my life was in danger. The only thing in my head was to move quickly.”

Still traumatised after his time in jail, his escape is a blur. There was a friend of the family, an agent, a passport, an airport, a plane. And suddenly he was in Britain, thousands of miles away from his wife, his parents, his baby son and teenage daughter.

Alone in a new country, he was to find that more than a decade of teaching experience counted for nothing.

“The people we come across are extraordinarily resilient,” says Juliette Stevenson, who works for the Refugee Council’s Refugees into Teaching project. “A lot of people have been working in high-level jobs - head of department, head of school - and now they’re forced to survive on minimum benefits. It’s quite a loss of self-esteem.”

Refugees into Teaching has 877 asylum-seeker teachers on its database and receives an additional 20 to 30 new calls every month. Around a third are from Zimbabwe, but there are 60 nationalities represented overall, including people from Iraq, Somalia and Afghanistan.

The process of being granted asylum in the UK can take years, during which applicants are forbidden to work and can be moved around the country with little notice. Science teacher Cyrille Solo, for example, arrived in Britain from Congo Brazzaville in 2002. After three years of waiting for his asylum claim to be processed, he, his wife and their son were taken to a detention centre and told they would be sent back to Brazzaville the next day. Around him, desperate refugees were smearing their bodies with their own faeces, hoping that this would repel the guards.

“It’s not in my nature to panic,” Mr Solo says. “I said to myself, `I’ve got my family. Maybe Britain isn’t the place for us.’ There’s some stuff you can control, but there are things you can’t. I’d tried my best. I’d been to see my MP. There was nothing more I could do.”

The family stayed for six days in the detention centre before a call came from the Home Office: they were free to leave the centre. But it would be another two years before they were granted asylum.

Alone in Britain, missing his family - “it was very, very hard for me; very hard” - Mr Sylla also had to wait for his asylum claim to be processed. “To be honest, I found it a bit shameful that I couldn’t go into a job straight away,” the 43-year-old says. And so, as soon as his refugee status was confirmed, he took the first job he could find: as a cleaner at a supermarket.

“The first thing was to find very quickly a job,” he says. “Sometimes you see yourself cry. Maybe you go to the toilet and cry - for example, when your wife calls and says the baby is sick, or that she has no money to buy food.

“And sometimes people, customers, can be a bit rude with you. It reminds you what you were doing before. You were the boss in a school and now you’re at the bottom. But that’s life. You just do your job properly.”

“People really want to rebuild their lives, get on,” Ms Stevenson says. “I’m in awe at people’s ability to continue. But teaching is a vocation: most just want to be back in the classroom.”

Beauty Ndlovu is among them. The 56-year-old first began teaching in her native Zimbabwe in 1972. “When I grew up, I came from a very poor background,” she says. “So if I see poor children it hurts me. I really want to help these children. I want to make sure they don’t go wrong with education.”

By 2008, she had worked as a headteacher for several years and had been promoted to schools inspector. But it was her voluntary work for a teachers’ union that attracted the attention of the government. She was imprisoned and kept in a filthy, rat-infested cell. After her release, her assistant told her that four men were looking for her; people around her were disappearing on a regular basis. And so she came to Britain.

Her asylum claim was processed relatively quickly and she began looking for a job. “I went to the Jobcentre and told them that I’m a teacher by profession,” she says. “I gave them my history and teaching background. I wanted to educate people.”

But when she applied for jobs, she was told that her 35 years of experience were irrelevant because they were not in UK schools. She was advised to apply for a voluntary position in a school. “If I started as an assistant teacher then I might get some experience,” she says. However, this too proved fruitless.

“The journey back to school is long and arduous,” Ms Stevenson says. “We get people who have different language skills, which schools are crying out for. But they’re struggling to get schools to take them on voluntary placements. It can be quite dispiriting.”

Competition for voluntary work can be as fierce as for paid positions, and the experience of many refugee teachers is that schools are biased towards teachers from developed countries.

“We have different accents,” says Praisemore Clifford Jabangwe. “They believe we won’t be able to communicate properly, speak properly. That brings stigma against foreigners.”

Mr Jabangwe taught history and PE for 12 years in Zimbabwe before fleeing for England, leaving behind his wife and two daughters. “I thought I would continue contributing to people’s education,” he says. “That’s my passion. I thought it would be easy simply to integrate into the education system in this country. But it’s been rather difficult.”

This sense of frustration is familiar to Ms Ndlovu. “I just thought, `Oh my God, if I was in education here I would be doing so much’,” she says. “I listen to anything on the news about education. Anything about education, I enjoy.”

But looking for work in schools has not been so pleasurable. “I don’t want to get stressed,” she says. “But I get so frustrated. Why can’t they accept that I have experience, that I’m a teacher? I want to offer my services for free, but they say I have to have experience here.”

Refugees can also find themselves with a series of bureaucratic hurdles to clear. For their teaching qualifications to be recognised in Britain, they must be able to produce certificates proving they have the equivalent of a GCSE in English, maths and science. This applies even if they have graduate or postgraduate qualifications.

“Unfortunately, bringing GCSE-equivalent certificates with you isn’t the first thing you’d think of when you’re trying to evacuate your family from somewhere,” says Ms Stevenson.

Mr Sylla sat his GCSE-equivalence tests in English and maths this summer: “In the beginning, I said, `I’ve got a masters degree. No one can get a masters degree without GCSEs.’ But that’s the way back into teaching, so I have to do it.”

Mr Solo, too, has had to sit his GCSEs: this was a precondition of being accepted on to a PGCE course.

A student in Brazzaville, Mr Solo’s interest in teaching developed only once he had arrived in Britain. Because of his science background, he was offered part-time work with a private-tuition agency, coaching A-level and GCSE pupils. “I saw how children from African backgrounds were struggling with science,” he says. “I wanted to give a hand. It’s amazing, transferring knowledge.”

Now, the 36-year-old is in his first year of a two-year science-teaching course at Keele University. He funds his studies with a part-time job sorting and delivering parcels: he works from 8pm until 2am, before waking up at 6am to make sure he arrives at university on time.

“It’s fine, it’s fine,” he says. “Children from minority families don’t have role models. They think that the only teachers in this country are mainstream white guys. So when they see me, they’ll think, `Oh my goodness,’ as if it was a miracle. It makes me feel good to think that they, also, can succeed.”

But success does not come easily for refugees. Of the 877 teachers on the Refugees into Teaching database, 219 offer the shortage subjects of maths and science. But since November 2008, only four have secured paid teaching positions.

Praisemore Jabangwe was offered week-to-week supply work by several schools. But although he tried repeatedly to persuade a school to employ him for six months, allowing him to attain qualified teacher status, none agreed.

“The schools referred me to the local authorities, but the local authorities talked about me finding a place first,” he says. “It’s so difficult and painful. And it makes me really frustrated: people haven’t given me the opportunity to show my abilities, my skills.”

Now, at the age of 41, he has given up on teaching and enrolled on an MA course in social work at Portsmouth University.

“It’s related to education,” he says. “The issue is to be helping people: that’s my passion.”

Ms Ndlovu, too, has moved into social work and is taking a BA in social and community development. “Yeah, I’m angry,” she says. “But my passion is to help. Through social work, I feel somehow connected to education again.”

With the help of Refugees into Teaching, Mr Sylla was able to find a volunteer placement in a Wakefield secondary. But, despite his 12 years’ experience, he struggled to find a permanent position. So he decided to quit his job at Tesco and retake his teacher-training qualification.

He has resigned himself to this bureaucratic hoop-jumping with benign equanimity. “My aim is to give everything I’ve got, in terms of knowledge,” he says. “If possible, I’d like to be a headteacher here, too. There’s a kind of happiness that comes with being back in the classroom. It made me happy. Makes me happy. Yeah.”