Gareth Gates was the Pop Idol runner-up whose boyish looks turned him into a heartthrob for millions. He was so popular that Smash Hits magazine said a day should be set aside in his honour. Perhaps not so well known, but equally important, he was also a godsend on Giles Bowmer’s first day of teaching practice.

“I told them I had a stammer, just like Gareth Gates,” says Giles. “They all knew who he was, so it was a way of helping them instantly understand what it was.”

Now in his fourth year of teaching, Giles, 27, has always taken the direct approach with his speech impediment. He thinks that if he tells the pupils himself, it is harder for them to use it against him. “Because I’m open and honest about it and it’s not a big secret, they can’t take the mickey out of it,” he says.

Stammering is commonly thought of as an involuntary repetition of certain sounds, but for Giles it takes the form of blocking: he gets stuck before certain words. Sometimes he can come up with an alternative but some words have to be said, a pressure that can exacerbate his problem. “If you’re introducing a new key word you can’t avoid it. I might write it on the board and say, ‘That is the word. I can’t say it, so you have to help me out’,” says Giles, who teaches at Oriel High in Crawley, West Sussex.

He always wanted to become a teacher, and admits it was down to his stubborn streak that he was not deterred by his speech impediment. “I’ve never been scared of my stammer, I never saw it as a disability and I wanted to prove that it wouldn’t stop me,” he says. Only once has he been on the receiving end of a negative comment - from his mentor at his first placement school. “She said I shouldn’t be on the course and, even if I passed, I would never get a job because of my stammer,” he says. “Then she wondered why my stammer got worse.”

His upfront policy generally works well, although there is still the occasional snigger. Dealing with parents can be more problematical. His stammer becomes worse over the phone, so he will email or write instead of ringing home if possible. Parents’ evenings are particularly stressful.

Giles says his confidence helps him overcome the problems his stammer brings. But for some people, their impediment seriously affects their self-esteem, which in turn makes their speech worse, says Cherry Hughes, education officer for the British Stammering Association.

Cherry, 64, worked as a secondary school teacher and deputy head in Cheshire until switching to work for the association 10 years ago.

She had a severe stammer until she was 21, when she devised her own self-help package. It took about seven years before her stammer disappeared completely. It was particularly troublesome because it meant she overspent on bus fares. Her inability to pronounce certain numbers meant she often bought the wrong ticket.

“I practised by sitting on a chair in front of a mirror pretending I was on the bus. The first time I did it I felt sick,” she says. But she finally succeeded so well that by the time she became a teacher, no one in school knew that she stammered.

Alisdair Cain’s colleagues at Morgan Academy in Dundee, Scotland, are also unaware of his stammer.

Speech therapy at primary school meant it all but disappeared, and at secondary school he was confident enough to take up debating, which is an interest he has maintained as a teacher by running the school’s debating society.

However, his impediment has not entirely gone away. Vowels at the start of phrases can be awkward, particularly in stressful situations, or where there is no alternative word.

“The only time it might be a problem in school is when I’m doing the register. Instead of just saying the name, I might say, ‘Where is so and so?’, or ‘Do I have so and so?’” says Alisdair, 24, who teaches history and modern studies.

Relaxation techniques help, as can an awareness of when a problem is looming so synonyms can be found in time. “If I stumble on certain words I can build up to them so I don’t take them cold,” Alisdair adds.

Therapy

John McIntosh, an English teacher at Eastwood High in East Renfrewshire, took a different approach, enrolling on the McGuire Programme - one of the most widespread forms of therapy for stammering - four years ago. Previously he had coped by adopting the techniques of many covert stammerers: avoiding words he knew would be difficult. Gradually, though, he became less confident in the classroom.

Part of the McGuire approach, which combines breathing control techniques with exercises to conquer the fear of speaking, is to be open about stammering. So when John returned to school after the weekend course, he put a note in every teacher’s pigeon hole and went into every classroom saying he had been working on his speech.

“I was expecting people to take the mickey, but the reaction was totally positive,” says John, 48. Since then he has given assemblies on stammering. “The more open I can be the better it is for me and the weaker the stammer becomes. The stammer gains power when I try to hide it.”

Kevin Phelps, 40, had also been a covert stammerer throughout his early teaching career. He adopted a theatrical teaching style and avoided difficult words. In phone calls to parents, he replaced the initial letters of his name with “H” to avoid saying two letters he found difficult, until he realised he was calling himself “Hevin Helps”.

It all unravelled when he went for a deputy headship interview. In front of a panel of eight, he fell apart. “I felt enormous panic straight away and all the skills I’d learnt as a covert stammerer left me. In the end I got up and asked to be excused.”

Kevin enrolled on the McGuire Programme. Nine months later he went for another deputy headship interview, this time writing on his application form that he was recovering from a stammer. He got the job.

That was 10 years ago, and he is now on his second headship at Tavernspite Primary in Pembrokeshire. “I’ve done a lot of public speaking and I’m now pretty confident most of the time,” he says. “But it is always in the back of my mind and I still do breathing exercises every day before I go to work.”

While Giles may have used Gareth Gates as an ice-breaker, unlike the pop star who also enrolled on the McGuire Programme to lose his stammer, he is determined to hang on to his. He classes himself as a vigilante stammerer and will deliberately stumble over words if someone behind him in a queue is getting impatient. “I would never be without my stammer. It is part of who I am and it has always been there,” he says.

One reason for keeping it is that he reckons it will prevent him from becoming a lazy teacher. Without the option of reading out passages from textbooks, he has no choice but to resort to more imaginative teaching methods.

THE TRUTH ABOUT STAMMERING

Stammering falls into three principal categories: repeating sounds, such as “ch-ch-ch-children”; prolonging sounds, such as “mmmmmmaths”, and blocking - getting stuck before certain words.

There is no known single cause of stammering, although there is evidence that both genetic and environmental factors can play a part. Physical trauma and a sudden increase in linguistic ability have been cited as possible causes.

Brain scans of adult stammerers found increased activity in the right hemisphere, associated with emotions, compared with the left hemisphere, linked with speech.

About one in 20 people go through a phase of stammering at some stage. Among under fives, twice as many boys stammer as girls. Among adults, that disparity increases to up to four times as many men as women.

There is no evidence of any change in the proportion of people who stammer over time. Stammering is found in all cultures and social groups.