MIKE ATHERTON'S ``bad back'' is in fact a degenerative condition called ankylosing spondylitis that cripples tens of thousands of people in Britain and gives him constant pain, the Lancashire player's club physiotherapist said last night.

Lawrie Brown, who was waiting for reports of Atherton's latest bout of suffering, berated those who have turned on the former England captain for his apparently downbeat attitude to playing.

``I think these people ought to think a bit about what he's going through and what he has been going through for almost all his playing career,'' Brown said.

``He isn't someone who can't raise a smile for the cameras. He's someone in almost constant pain suffering from a disease that would have stopped lesser men playing anything, let alone top-class cricket.

``It's about time that people stopped moaning about him and realised that this is one incredibly brave bugger who should be a role model for anyone with this condition.''

Brown added that Atherton, 30, had been reluctant to let anybody know about his condition, which is hereditary and ended the football career of his father Alan. ``I don't know Athers' father very well, but he does have pronounced curvature of the spine and I suppose that's what Michael has to look forward to.

``Until three years ago he didn't want anyone to know about this because he was afraid it would affect his career. He thought it might put a question mark over his England captaincy if they knew what he was suffering from.

``But he doesn't moan about it, he just gets on with the game and plays through what must be a lot of pain. Every so often he gets a flare-up like he has now and then he has to have a hydrocortisone injection into his sacroiliac joint, which normally puts things right after a day or two.

``I think it's marvellous, absolutely extraordinary really, the level at which he has been able to play the game and to keep playing the game. Over the last 12 years he has just gone on getting better and he has almost all that time had back pain. Sometimes it's worse, sometimes better, but he lives with it.

``I'm sure most of the people he plays with don't know, and you can tell that those who write about him don't. I get sick of reading criticism of him not being able to raise a smile on tour or something like that.''

Brown said that he had tried to persuade Atherton to do his special therapeutic exercises to allay the onset of pain. ``But, human nature being what it is, he only does them when he feels it getting bad, when he should be doing them as an insurance against the pain starting up again.''

In 1992 Atherton had an operation in a private hospital in Nottingham to fuse together his fourth and fifth vertebrae after he suffered a slipped disc.

``He had the ankylosing spondylitis before he had the operation and he had it afterwards. That was just something in addition to what he normally has.

``It's a great tribute to his strength and his will that the scans we've got of him now aren't much worse than when he first developed it. He has stuck to the exercises and the training so well.''

Brown said that cricket was unlike football in that a sufferer of the disease could play without much risk of doing injury to himself. ``If you're headering a ball, that's something that could do you a lot of damage.''

In addition to his back pain, Atherton's disease also causes him to suffer stomach upsets that vary in severity, but so far he has avoided the sight problems that also accompany the condition.

Ankylosing spondylitis has raised a question mark over Atherton's participation in Friday's first Test in Brisbane, but it need not curtail his cricket career, according to Britain's leading expert in the disease said.

Dr Andrei Calin, of the Royal National Hospital for Rheumatic Diseases in Bath, explained that the disease, known as AS, has its worst effects among sufferers in its eary stages and the average age for diagnosis is 25.

Atherton, 30, was first diagnosed with the condition, which affects young men nearly three times as often as young women, in his early 20s.

``If someone is still participating in top-class cricket at the age of 30 and you have had the disease for eight or nine years, there is no reason why AS alone will stop you from going on to fulfill a normal professional career,'' Dr Calin said.

He has two patients under his care, one a Premiership footballer and one an Olympic swimming gold medallist, who he has been able to reassure that they will not have their sporting days cut short by AS, even though the disease is incurable and gradually degenerative.

``If you look at Atherton, his posture, his ability to run around and stay batting for long periods, it's obvious that he's in the top 10 per cent of sufferers from the disease and there's no reason why he shouldn't continue for another 10 years at the top of his sport,'' Dr Calin said.

``But he does need to be seeing a good rheumatologist. A vast majority of patients carry on with a full-time professional career until normal retirement age.

``Being a sportsman is the best thing for an AS sufferer because it involves lots of exercise. The worst thing is being a doctor or a journalist and spending all your time sitting down and looking at a computer.''

Flare-ups of the symptoms - excruciating back pain that can spread into the hips and ribcage - such as the one threatening to prevent Atherton opening England's Ashes account in Brisbane, are common, but can be controlled with drugs and physiotherapy.

Dr Calin is also chairman of the National Ankylosing Spondylitis Society [NASS], who have helped more than 70,000 sufferers in Britain in the past two decades.