Interview: Sir David Jones: Sir David's toughest battle amid his business triumphs

He refused to give in to the disease; instead, he says he split himself into two people.

"There was the David Jones the chief executive of Grattan and Next and then there was the David Jones with Parkinson's Disease. I kept the two separate," says the 67-year-old grandfather.

"I didn't even tell my wife for three years. I thought if people knew I had Parkinson's they would think that it would affect my business judgment. There really wasn't much known about it back in 1982."

Now, after nearly 30 years with the disease he has taken the difficult decision to stand down from his high profile business career. A decision you feel he has still completely to come to terms with, understandable for a man used to being at the forefront of the retail world, lauded for saving Next and many other retail giants.

"It was a hard decision but it was getting much harder to do a normal day's work," he says. "It was wonderful if I was responsible for saving the company (JJB Sport) from administration last year, but because of my illness failed it this year. It was the only decision I could make. I maybe shouldn't have taken it on," he says thoughtfully, "but a huge number of people would have lost their jobs."

Sir David was diagnosed with Parkinson's Disease on July 25, 1982 and he had just taken over as chief executive at Grattan.

"At that time, a lot of people considered Parkinson's to be a mental illness not a physical one," he says.

"I went into the car park of the Yorkshire clinic after the doctor had just told me and thought, 'What the hell am I going to do'. I was 38 years old. I knew people would think I wasn't capable of running an international company. I would lose my job and I was a total workaholic. I decided then and there that I wasn't going to tell anybody."

Sir David has a slow developing form of Parkinson's which allowed him to keep his secret for over two decades. On the day I met him at his palatial Ilkley home he was having a "bad day". He has a pump which delivers medication straight into his blood stream; before it was fitted he was taking more than 40 tablets a day.

"I am trying a new drug at the moment and they are trying to get the levels right." As a result, it takes more than an hour for Sir David to get going in the mornings with the help of his wife, Ann.

When the drug levels aren't quite right he suffers something called dyskonesia, which means his hand and face can spasm uncontrollably. His speech is sometimes slurred and his walking can be affected, leading to concerns that people might think he was drunk.

"When I did eventually tell people in 2001 that I had Parkinson's some colleagues were relieved as they suspected that I might have a drink problem.

"I'm a mover not a shaker," he says with the humour which has helped him cope with this cruel condition over the years.

"Some people develop tremors and some spasms. The problem with Parkinson's is that everyone is different."

His battle with Parkinson's makes his achievements even more remarkable. When he took over as chief executive of Next in 1988, it was on the brink of collapse but he built it into one Britain's biggest fashion business. Under his leadership Next's stock market value increased from a low of 25m to a high of 3.5bn.

He still sees what he did at Next as his biggest achievement. But the fact he was also battling Parkinson's makes Sir David even more remarkable.

"I was extremely high profile during that time and I had to do everything I could to hide the symptoms."

When in 2001 he decided at last to speak about his condition, he wrote about it in his autobiography Next to Me. It also gave him the freedom to become actively involved in finding a cure for Parkinson's.

With a group of colleagues he set about creating the Cure Parkinson's Trust, a charity dedicated to raising money for research. An annual ball organised by Sir David raised 500,000 a year.

"The Parkinson's Society (this month rebranded Parkinson's UK) does a brilliant job supporting those with the condition, but we felt more needed to be done to raise money just for research," he said.

Parkinson's is caused by the malfunction of part of the brain which manufactures dopamine. The Cure Parkinson's Trust's research is looking at ways to regenerate the brain cells which have stopped working. They are already carrying out clinical trials.

"I am 67 and before I am 70 we will have a completely new way of dealing with the problem."