Fifty-five babies died or were permanently brain-damaged during secret government trials to test a new vaccine for whooping cough, the Daily Express can reveal.

The trials were conducted on thousands of pre-school children even though the drug was at a highly experimental stage.

Nobody told the parents that their babies could be at risk from the tests which also caused convulsions, and permanent disablement. Olivia Price from the Vaccine Victims Support Group said families now need proper compensation to help care for their loved ones.

She added: "This is unforgivable. The Government knew damage could be done - anyone with a baby should have the freedom of choice whether to they wanted their child to risk this. The fact that these parents were not told anything and their children were left so damaged is nothing short of abuse."

The trials, based in London, Bradford, Newcastle and Liverpool, were carried out by the Medical Research Council between 1948 and 1956. The victims are now in their 40s and 50s and still need round-the-clock care.

This month the Daily Express launched a campaign for proper compensation for hundreds of children left brain damaged and paralysed after suffering adverse reactions to routine vaccinations.

For many years the Government refused to accept the vaccine could have caused damage. However in 1979 the Government granted those who could prove their children were over 80 per cent brain damaged a one-off "interim" payment of £10,000.

This was only enough to look after a brain damaged child for a year. The families have received nothing since.

The 55 babies were part of an NHS experiment to find out which of various drugs could successfully vaccinate against whooping cough. After each dose, the child was monitored for a month by a "nurse investigator" and progress was reported. The disastrous side-effects were not acknowledged by the health service for decades.

Ian Stewart MP from the all-party parliamentary group on vaccine-damaged children said he wanted the Government to examine the issue of the trials. "Such allegations should be investigated and are of great concern. However Government's first focus is the inadequacies of the existing payment system which hasn't addressed the problems faced by families with damaged children."

Elizabeth Skates, 64, of Dulwich, South London, was the mother of a robust and happy baby called Jackie. In 1956 she took her to a welfare centre in Clapham where a nurse suggested she should give the child a vaccination against whooping cough.Jackie reacted violently and was rushed to hospital on the brink of death. Now 44, she has severe brain damage and is still in nappies. She is paralysed down her right side and has fits every day.