Their fears were brushed under the carpet because the Department of Health was worried that any adverse publicity about vaccines could cause a panic, with parents refusing to have their children vaccinated. The true feelings of those involved have emerged through evidence given to the BSE inquiry under Lord Phillips of Worth Matrvaers, which is due to publish its report next week.

Sir Richard Southwood, who led the first inquiry into BSE in 1988, soon identified that the greatest risk of human transmission lay in the injection of contaminated material in vaccines, and identified this as a priority area for action. In a meeting in May 1988, the Government’s chief medical adviser, Donald Acheson, called for “urgent advice”.

Sir Richard wrote a letter circulated to officials in which he said “the possibility of human infection is moderately high”. He also wrote to the Committee on the Safety of Medicines three times asking for action. But his report played down the threat by saying that the risks “appeared remote”. He told the Phillips inquiry that the committee used reassuring language because it did not want to cause a flight from vaccines and have the deaths of children on their consciences.

They were also told privately by the Health Department that steps would be taken to reduce the risks. But in writing to the vaccine manufactures, the department merely reiterated that the risks of infection through medical products was remote. In January 1989, the CSM ruled that future vaccines would be taken only from herds certified to be free of BSE, but took no action to remove stock from the shelves made before this change was introduced. The vaccines continued to be used until 1993, and included MMR (measles, mumps and rubella) and vacccines against diphtheria, tetanus and whooping cough. Norman Baker, the Liberal Democrat MP who has campaigned on the issue, says this was “potentially criminally negligent”.

The Health Department says that if vaccinations had been stopped there would have been a risk of epidemics, and deaths, among children. This risk was real, while that of transmission of BSE was “remote and theoretical”.

Health ministers have given evidence that they were never properly briefed. Kenneth Clarke, a former Secretary of State for Health, has said that had he been told he would have ordered the vaccines to be withdrawn. So far, no evidence has emerged which implicates the vaccines in variant CJD, the human form of BSE, which has claimed 75 lives. Most scientists still believe that eating contaminated beef is a more likely source, although the young age of many vCJD victims has led others to suspect a role for vaccines.

The latest alarms over the oral polio vaccine do not change the picture. Even if it was contaminated, eating the infective agent for BSE is less dangerous than being injected with it. Celltech, which now owns Medeva, the company responsible for the vaccine, and the Health Department believe the risks from the vaccine are “incalculably small”. Credibility of government assurances in this area is not very high.