The great measles epidemic that was supposedly going to sweep Britain this year was never going to happen, new evidence suggests.

A £20m national immunization programme went ahead, nonetheless, and now at least 300 children are claiming they have been permanently damaged by the vaccine, which government officials and doctors assured them had no major side effects.

About 80 parents are seeking legal aid as the first wave of cases makes its way to the High Court.

The British government gave the substantial order to the two drugs companies which had sufficient supplies of the vaccine still in stock. The government has said it was unable to offer the contract on the usual competitive tender basis because of the emergency it was facing.

Dr Richard Nicholson, editor of Bulletin of Medical Ethics, is calling for an independent inquiry because "the campaign's protagonists misled millions of parents into allowing needles to be stuck into their children for purposes other than those given in public".

After sifting through scientific papers, Dr Nicholson has concluded that there was no evidence to suggest there was going to be a measles epidemic this year. In fact, new research published recently (Epidemiology and Infection, 1995; 115: 139-56) would suggest no epidemic for another five years, at least if more believable assumptions were used. Even as it stands, government fears of 50 deaths caused by the epidemic were grossly exaggerated and were based on old data, argues Dr Nicholson.

The government also underplayed the dangers of the vaccine. Data collected by the Communicable Disease Surveillance Centre showed that one serious adverse reaction a bleeding disorder called thrombocytopenic purpura was five times more likely than was previously thought.

Finally, Dr Nicholson described the campaign as "a gift horse" for the two drug companies, which still had vaccines in stock intended for use with the combined measles-mumps-rubella (MMR) jab. The government had their MMR stocks suddenly withdrawn after discovering the strain of the mumps element used in their MMR vaccine caused meningitis in at least 1 in 11,000 cases.

The stocks of the MR vaccine were still current, but had to be used by last autumn, just when the campaign took place. "The campaign provided a very lucky break for the two vaccine suppliers," said Dr Nicholson (Bulletin of Medical Ethics, August 1995).

Cases of meningitis were as high as one in 500 children vaccinated with the MMR injection in one area of Japan, researchers from Kyushu University, in Fukuoka, Japan have discovered. They studied cases between 1990 and 1993, when the Japanese government finally withdrew the domestically produced version of the MMR vaccine (The Lancet, September 9, 1995).