Tory Chief Whip has lived with MS for six years

David Maclean, the Tory Chief Whip, plans to appear in the House of Commons in future brandishing a stick. A proper cromach, or shepherd's crook, it will come in useful for reining in Tory sheep who stray from the party line, but its true purpose is more dismal. After six years in which he has hidden his illness from colleagues and friends, Mr Maclean came clean yesterday and revealed he has multiple sclerosis.

Not that there was anything dismal about the confession. With typical bravado, he said he had no intention of giving up his job, no intention of using "some lousy, metallic, expandable NHS tube" to keep him upright and no intention, when the time came, of using a dull NHS wheelchair. He will be looking for a turbo-charged model.

The MP for Penrith and The Border was diagnosed in August 1996 with the disabling disease and decided this week that he had had enough of fobbing off inquiries about his stiffness with the line that it was just a touch of sciatica or cartilage problems. "If I'm wimping out, what sort of lesson is that to the party? As Chief Whip you have got to show an example of fighting spirit," he said in a newspaper interview.

At 49 after "several fairly even years", Mr Maclean suffered a sudden deterioration around Christmas, which appears to have prompted his decision to go public.

There are two main forms of the disease: the relapsing- remitting form in which patients suffer periodic attacks, often beginning with blurring of vision, from which they partly or totally recover, and the primary progressive form, which tends to start in the spinal cord and whose earliest symptom is difficulty in walking.

Mr Maclean, a former Home Office minister, was described as having progressive MS, which is the rarer of the two forms, accounting for one in 10 of cases. It tends to start later than relapsing MS, for which the peak age is 30.

Giles Elrington, consultant neurologist at St Bartholo-mew's and The London NHS Trust, said there were difficulties in distinguishing a temporary relapse from permanent progression of the disease.

"It is entirely possible that his new disability will go away and be shown to be a relapse. But it is a reasonable strategy to assume the worst. If it is the onset of progressive MS it is difficult to say what the future holds. He may still be walking at the age of 70 or he could be in a wheelchair in a few years."

John Zajicek, consultant neurologist at Derriford Hospital, Plymouth, who is studying the effects of cannabis derivatives on MS, said Mr Maclean's fighting spirit would help. "This is an unpredictable disease and living with uncertainty is very difficult. If you have got a positive outlook that is very important."

Treatments for MS are limited to drugs such as beta interferon, which controls the symptoms of relapse caused by inflammation of the myelin sheath surrounding the nerve fibres. There is no treatment for progressive MS but some compounds have shown promise against similar diseases.