Although it is unclear what causes MS, some doctors believe that it is the immune system itself which attacks the brain and spinal cord, leading to inflammation and pain, disability and in severe cases, death.

In the new treatment, specialists use a high dose of chemotherapy to knock out the immune system before rebuilding it with stem cells taken from the patient’s own blood.

Stem cells are so effective because they can become any cell in the body based on their environment.

“Since we started treating patients three years ago, some of the results we have seen have been miraculous,” Professor Basil Sharrack, a consultant neurologist at Sheffield Teaching Hospitals NHS Foundation Trust, told The Sunday Times.

“This is not a word I would use lightly, but we have seen profound neurological improvements.”

During the treatment, the patient’s stem cells are harvested and stored. Then doctors use aggressive drugs which are usually given to cancer patients to completely destroy the immune system.

The harvested stem cells are then infused back into the body where they start to grow new red and white blood cells within just two weeks.

Within a month the immune system is back up and running fully and that is when patients begin to notice that they are recovering.

Holly Drewry, 25, of Sheffield, was wheelchair bound after the birth of her daughter Isla, now two.

But she claims the new treatment has transformed her life.

“It worked wonders,” she said. “I remember being in the hospital… after three weeks, I called my mum and said: ‘I can stand’. We were all crying.

“I can run a little bit, I can dance. I love dancing, it is silly but I do. I enjoy walking my daughter around the park in her pram. It is a miracle but I can do it all.”

However specialists warn that patients need to be fit to benefit from the new treatment.

“This is not a treatment that is suitable for everybody because it is very aggressive and patients need to be quite fit to withstand the effects of the chemotherapy,” warned Prof Sharrack.

Charities welcomed the research but also urged caution.

Dr Sorrel Bickley, Research Communications Manager at the MS Society said: “This new study reports very encouraging findings, which add to a growing body of research into stem cell transplantation in MS. However, there are limitations to how we can interpret these results because there was no control group used, which means we can’t be sure the results are robust.

“Momentum in this area of research is building rapidly and we’re eagerly awaiting the results of larger, randomised trials and longer term follow up data.

“New treatments for MS are urgently needed, but as yet there are no stem cell therapies licensed for MS anywhere in the world. This means they aren’t yet established as being both safe and effective. This type of stem cell therapy is very aggressive and does carry significant risks, so we would strongly urge caution in seeking this treatment outside of a properly regulated clinical trial.”

The research was published in the Journal of the American Medical Association.