Famous stammerers include Marilyn Monroe and Charles Darwin (wiki commons)

Politician Ed Balls has spoken out on International Stammering Awareness Day about his struggle of living with a stammer.

The shadow chancellor told ITV's Daybreak that he found out that he had the speech impediment only when he became a Cabinet minister and it was difficult to engage with parliamentary debates.

It is estimated that 300,000 people in the UK stammer in the workplace and the British Stammering Association (BSA) is looking to help support people with stammers in its first ever Employers Stammering Network (ESN).

A survey by the BSA found that half of people who stammered did not put themselves forward for a promotion because of their speech impediment.

A further two-thirds said they held back their ideas at work because they worried speaking up was a problem. Over 80% said it would help if their manager understood their condition better.

Norbert Lieckfeldt, CEO of the British Stammering Association, said: "Getting it right for colleagues who stammer isn't difficult. However because of the stigma attached to stammering due to the many misconceptions around it, those who stammer are still too often shying away from asking for the support they deserve.

"The ESN will enable employers to support their staff better, foster greater loyalty and draw on the undoubted talents and skills of people who stammer who, otherwise, might decide to work for the competition. Ultimately this work will open the door to a wider appreciation in UK businesses about what makes for good communication in the workplace"

IBTimes UK looks at some of the most famous stammerers and how they overcame their speech impediment:

King George VI

Subject of the Oscar-winning film The King's Speech, King George VI suffered from a severe stammer for many years and hated public speaking as a result. When King Edward VIII abdicated and George was crowned king, he overcame his stammer with the help of Australian speech therapist Lionel Logue, who helped him with breathing exercises and rehearsals.

Elvis Presley

Elvis stammered from a young age and his doctor recommended his mother take him to singing lessons to help him overcome his speech impediment as it uses voluntary diaphragm usage, unlike speaking which is involuntary, the Houston Press reports. Jerry Lee Lewis said the singer continued to stutter into adulthood when he was upset or agitated.

Marilyn Monroe

Marilyn Monroe's famous breathy voice was a result of her childhood stammer, which she struggled with for two years of high school. A speech therapist taught her breathing techniques to help her speak fluently. Her stammer returned in the final few months before her death, when stress from her personal life because increasingly prominent.

Emily Blunt

Earlier this year, Emily Blunt hosted American Institute for Stuttering's annual gala. She suffered with a stammer as a child and she has credited a teacher who encouraged her to take part in a school play despite her stutter as helping her to overcome it.

In an interview with W magazine, she said: "My parents took me to speech coaches and relaxation coaches. It didn't work. Then one of my teachers at school had a brilliant idea and said, 'Why don't you speak in an accent in our school play?' I distanced myself from me through this character, and it was so freeing that my stuttering stopped when I was onstage. It was really a miracle."

Joe Biden

Vice president Joe Biden has spoken about his stammer and how he overcame it a number of times. He suffered from a stutter as a child and was teased by both his classmates and teachers.

He told People magazine: "I was in 7th grade at St. Helena's and I still remember the reading 'Sir Walter Raleigh was a Gentleman.' I remember reciting, 'Sir Walter Raleigh was a gentle man'. The nun said: 'Master B-B-B-Biden! What's that word?' She wanted me to say gentleman. But by then, I had learned to put my sentences into bite-size pieces and I was reading it: 'Gentle. Breath. Man'."

Tiger Woods

Tiger Woods has said he had a stammer as a child and got over it through hard work and practice. He told CBS: "The words got lost, you know, somewhere between the brain and the mouth. And it was very difficult, but I fought through it. I went to a school to try and get over that, and I just would work my tail off."

Samuel L Jackson

Actor Samuel L Jackson also had a stutter as a child and speaking at the American Institute for Stuttering's annual gala, he told how he used a swear word to help him with his speech impediment. According to Vulture, he said: "Growing up a stuttering black kid in Tennessee in the fifties didn't quite make me think I was going to end up in a place like this.

"I'm still stuttering. But I figured out a way to do it. And some days, the best thing for me to do is say my favourite word, and I get through it: 'Motherfucker!' ... I say it and it helps, like even if I just say it to myself, under my breath. I don't stutter when I say that word."

Julia Roberts

Julia Roberts has said she stammered as a child but has never gone into great detail. She has since become one of the highest paid actresses in the world, commanding £15.5m for Mona Lisa Smile.

Her brother Eric also suffered from a stutter and has spoken about it in Andy Warhol's Interview magazine: "I read a lot when I was little because I had the worst stutter in the world.The the the wa-wa-wa-wa-wa-wa-water is cold'. And the class cracked up. I suppose it was funny, but it was so painful for me."

Winston Churchill

Winston Churchill was considered to be one of the best speakers of his time and he went to great lengths to hide his speech impediment. He would write all his speeches well in advance and spend weeks practicing and memorising them. Churchill is also believed to have had a lisp. "My impediment is no hindrance," he once said.

Charles Darwin

Charles Darwin occasionally spoke with a stutter and often pronounced the first word of a sentence with a stammer, particularly those beginning with W. He was also slow at forming the wording of an argument. Other historical figures who spoke with a stammer include Isaac Newton, Aristotle and Charles I.