There is a moment in The King's Speech, the multi-Oscar-nominated British film, when Queen Elizabeth, played by an icy Helena Bonham Carter, meets speech therapist Lionel Logue for the first time to discuss her husband's chronic stammer - before Logue realises his future patient is a royal. She explains: "My husband's job requires a lot of public speaking." Geoffrey Rush's Logue retorts: "Then he should change job."
But the future King George VI, played by Colin Firth, cannot change job. His job is to be the voice of the nation on the eve of the Second World War.
It might not be quite as stressful as the king's live radio broadcast as Britain declared war on Germany, but for a 13-year-old with the same impediment, a barmitzvah speech can be just as terrifying. And like George VI, it is a job that is hard to turn your back on.
Football agent and regular sports pundit Jon Smith has had a high-pressure career. When he was chief executive of First Artist sports agency, he represented 200 footballers, including Diego Maradona. But he could barely speak a word until the age of 16.
Raised in an Orthodox household, his barmitzvah speech was almost a disaster. "I could do the portion because I could sing. Your brain doesn't compute singing with the same fear of words. But the worst part was the speech at the lunch afterwards. That took twice as long to get out as the portion."
Smith had stammered ever since he could remember. "My real name is Jonathan but I became Jon because I would say "J-J-J-J-J-J-J" and eventually I would get the Jon bit out. People were so relieved I'd got something out of my mouth, they would say: 'Hi Jon'."
It was after his mother died when he was 15 that his dad found a "miracle cure" at an unusual school in Jersey. "I was basically 'cured' by being beaten up. I went to a school run by a man called Bill Kerr. He maintained stammering was a fear of words and if he could make your brain understand that stammering was scarier than speaking, he could cure you.
"We had to stand bolt upright, speaking slowly and if we stammered he hit us. Slapped round the face punched in the stomach, smacked in the back of the head. I ordered soup one night and I stammered and he dunked my head in the bowl. But after three days I was speaking for the first time in my life."
Now a patron of the British Stammering Association, he says he is indebted to Kerr for teaching him tricks which have helped him forge a career as a sports pundit, appearing on television and radio. "He taught us how to use words, and how to know when someone's using speech to intimidate you. So I have this whole bag of tricks now. It has served me so well.
"But I do Newsnight with Jeremy Paxman and I still have to go to the toilet for a couple of minutes before to compose myself like Bill Kerr told me."
For London tax specialist Paul Fox, 32, help came at a much later age. His barmitzvah is a painful memory. "Things went terribly with the speech. I practised and practised it and I really knew it. But when it came to it, I said roughly four words. And then I cried. Then the toastmaster took over and did it for me."
He found speech therapy tough as a teenager and his speech problems continued into adulthood. It was only when he proposed to his wife Charlotte four years ago that he found a way to cope with his stammer. "I really wanted to make a speech at our wedding. I saw an interview with the singer Gareth Gates. He stammers and had just been through treatment called the McGuire programme. I thought I would give it a final go.
"It's a four-day programme training your diaphragm to control your breathing. It combats the physical problems and reduces the fear. They make you do a public speaking event - you go into the town centre, stand on a soapbox, and speak. For me, it was an outpouring of emotion; it was the first time I had spoken like that.
Fox went on to deliver his groom's speech in front of 200 guests. "It went brilliantly," he says.
Sharon Cohen gave up her batmitzvah studies because of her stammer. "I did the training for it but never really took it to completion."
The 48-year-old human resources manager first remembers stammering at the age of seven. "It was a point of amusement for other children. I never had any real solution for it. It was something that other members of the family had and I suppose my mother thought it was just the way it was and as far as she was concerned, it never made any real difference to her. I was still her daughter and she loved me anyway."
Like Smith, she found an unorthodox cure in an unlikely place. "When I was 18, I discovered that the Scientologists ran a course on communication. "At the time I didn't know what Scientology was. I just did the course and found that I got huge improvements in my speech and general self-confidence. Now I have virtually no trace of a stutter."
Judith Weisz, a children's speech and language therapist at Norwood family charity for eight years, says stammering affects about five per cent of children at some time in their lives and that approximately 1 per cent of these children will continue to stammer into adulthood.
She adds: "The current view is that there isn't one particular factor that causes stammering, but rather it's more likely to be a combination. Children who stammer show the same spread of intelligence levels as the rest of the population and stammering crosses boundaries of race, culture and class, although boys are more vulnerable than girls. The important point is that parents shouldn't think they cause stammering in their children, and should not blame themselves."
Smith, Cohen and Fox are keen to dispel the idea that their stammering was caused by a traumatic childhood. Cohen says: "At the time I was very down about it, but I do feel that with my mum being so close to me and helping me in any way she could, I was actually quite fortunate."
Fox says he knows he can never be cured of his condition. "I know I can't get fluency, but I can be a strong speaker. There's always bad days when I'm tired or stressed when I have to go slow again."
Smith agrees that there are always moments when the old fear creeps back. "Once I had to give an introduction for the then Culture Secretary David Mellor. And I clammed up. I couldn't say a word. And all the eyes are on you. It's exactly like The King's Speech."