The Department of Social Security's chief medical adviser has cast doubt on the seriousness of most long-term back pain injuries which allegedly prevent sufferers from working.

Professor Mansel Alyward provoked controversy at the Davies Lavery back claims conference at Lloyd's, by claiming it was a myth that back pain had reached epidemic proportions.

He told the conference: "Chronic back pain is one of the subjective complaints society has at the moment."

Prof Alyward, a back pain and rehabilitation expert, revealed the number of working days lost to back pain has increased from 10 million in 1955 to 90 million in 1995. The cost of social security benefits paid to people with back pain is £1.8bn per year, representing a significant burden to the taxpayer.

Prof Alyward said: "What there is, is an epidemic increase in chronic disability and rise in social security benefits for people with back pain."

He said this conflicted with evidence from the Health and Safety Executive that there had been no major change in work-related back injuries – in fact the working environment has become safer.

He thought that cultural reasons were to blame: "As a nation, part of our culture is to accept that people with back pain cannot work."

He attempted to redefine the problem: "Let's not talk about back pain – lets talk about activity intolerance, I prefer to say it's a back pain problem with medical aspects."

He said the pain of sufferers who had failed to recover after medical help could be the result of subconscious psychological factors.

Their recovery and return to work may be impaired by family members who unwittingly conspire to keep a sufferer disabled for personal or financial reasons.

"Pain alone is not a sufficient cause to delay resumption to work. We need to send this message out to clinicians, lawyers and the insurance industry, who should understand it is not a medical problem and we can do something about it."

He said there were signs the medical profession was responding to this radical change in thinking.

Referring to a research paper he has written for the Britsh Medical Association (BMA), Prof Alyward said this showed the alleged epidemic of back pain was abating – the number of people on disability benefits has fallen below one million, representing a saving of £4bn.

He said however, that he was not convinced that early intervention by insurers and doctors helped encourage back pain suffers to return to work more quickly.

"Physiotherapy will assist some people, but often we find we are only identifying long-term cases earlier."