JK Rowling has revealed that she kept Harry Potter a secret from her mother, who died knowing nothing about the now world-famous wizard.

JK Rowling has revealed that she kept Harry Potter a secret from her mother, who died knowing nothing about the now world-famous wizard.

The author admitted that she began writing about Harry months before the death of her mother, Anne, aged 45, who had battled Multiple Sclerosis for years.

But to her regret Ms Rowling decided not to tell her mum about the magical stories of wizardry which would transform her into a household name across the globe.

The revelation was made during an interview for a documentary to be broadcast tonight discussing why Scotland has the highest MS rates on earth and why so little is done about it. The BBC Scotland programme is presented by reporter Elizabeth Quigley, whose own diagnosis with MS inspired her to try to find out the causes of the debilitating disease and how best to tackle it.

Speaking to Ms Quigley on the programme, Ms Rowling - who is patron of the Multiple Sclerosis Society Scotland - said: "I started writing Harry six months before she died. That's obviously a real regret because I never told her I was even writing it. She knew I wanted to write. I'm not sure how seriously she took it. She never knew anything about Harry Potter at all."

She described how she witnessed her mother's condition deteriorate as she grew up and realised that her mother was not the "invulnerable" woman she had believed her to be.

She said: "I was 25 when she died. When I left home she was walking unaided, by the time I graduated she was in a wheelchair and needed a walking frame in the house. It was awful to watch."

The writer also criticised the lack of funding for MS, which she said was well-known as the "Cinderella" of modern illnesses.

She added: "It is a frustration to those of us whose family members do have MS that so little is being done."

The first sign that something was wrong with her mother was a persistent numbness which gradually spread from her arm across her torso. Eventually doctors told her that she had MS.

For Ms Quigley it was an "annoying" tingling in her face which eventually led to her own diagnosis, while she was a political reporter for BBC Scotland.

After eight years, she now walks with a stick, and said that she and her husband, SNP Finance Secretary John Swinney, were determined not to let MS dictate their life and work. Tonight's programme, entitled Scotland's Hidden Epidemic - The Truth about MS, highlights the country's unexplained position as the place where more people have MS than anywhere else on the planet.

An estimated 10,500, or one in every 500, are thought to have the unpredictable disease, and rates are still rising. The largest numbers are found in the far northerly reaches of Scotland on Orkney and Shetland.

Several theories about the causes of the disease are explored during the documentary, including the idea of a Scottish "MS" gene making people more susceptible. Other possible links revolve around the idea that lack of sun and Vitamin D play a role. During the programme, Ms Quigley visited Canada where many descendants of Scottish emigrants also have MS. There, a national database set up in the 1970s is helping experts conduct promising trials of possible treatments.

In Scotland, to Ms Quigley's "almost embarrassment", far less has been achieved with work only just starting on a similar nationwide database. She also notes that the Scottish Government has funded no research into MS.

Work at Edinburgh University, financed by Ms Rowling, is said to have the potential to find a cure, however, bringing a glimmer of hope.

Speaking after a preview of the programme at Edinburgh's Filmhouse yesterday, Ms Quigley said: "I'm not holding out for a cure for me but maybe we can turn the negative Scotland's position as the world MS capital into a positive with a future cure."