Arnold Simanowitz, chief executive of the charity Action for Victims of Medical Accidents (AVMA), said that the growing burden of medical negligence claims on the NHS, which runs to billions of pounds, would be much higher if all those who suffered negligence claimed compensation.
At least 82,000 of an estimated 320,000 medical accidents in the NHS each year were due to negligence, but only 15,000 led to legal action, he said.
"If all 82,000 took action we would be in a lot more trouble than we are today. And many patients are going without the compensation they need," Mr Simanowitz added.
The National Audit Office reported last week that the NHS was facing a bill of pounds 2.8 billion for negligence claims. Although many cases fail to win compensation, many more are never begun because the patients do not know that they have been victims of negligence.
Estimates of the number of medical accidents, based on an American study, were presented at a conference in London organised by the King's Fund and AVMA yesterday.
Mr Simanowitz, speaking in the presence of the Health minister Baroness Hayman, said that the only figures collected centrally by the Government related to the cost of medical negligence claims. "It is a scandal that so many words have been written, so many conferences held and so many initiatives taken by hospital trusts, yet we still do not know the actual size of the problem," he said.
Reliable figures were essential so that targets could be set by health authorities for the reduction of medical accidents. The figures from the 1989 Harvard Medical Practice Study, which had never been challenged, were the best available at present.
That study, of 30,000 hospital patients in New York State, found that 3.7 per cent were victims of a medical accident. When extrapolated to the 8 million hospital patients in the UK, this translates to 320,000 medical accidents a year. It takes no account of negligence by GPs or in accident and emergency departments, however.
Mr Simanowitz said the official reason for not collecting central figures was the difficulty of deciding what counted as a medical accident, but suggested that commercial organisations brought in by hospitals to help to cut clinical risks might provide a helpful starting point.
Gerard Panting, head of policy at the Medical Protection Society, the doctors' defence body, said it was a "racing certainty" that the total number of cases of negligence was higher than the number of claims.
He added: "We share Mr Simanowitz's disgust at the failure to collect central figures. We are told to learn from our mistakes, but if we don't know what our mistakes are we don't know where to focus our attention."
Lady Hayman told the conference that the Government's Chief Medical Officer had convened an expert group to consider what the NHS could learn from medical accidents. It is due to report by the end of the year. She said most victims sought no more than a frank explanation and an assurance that it wouldn't happen again.Reuse content