Health Minister Hazel Blears yesterday admitted an astonishing catalogue of blunders over vaccine safety.

She revealed that the Government body supposed to make sure vaccines could not transmit deadly CJD made a series of basic errors.

It means polio vaccines containing bovine materials are still being used long after Ministers said they had been withdrawn because of fears over BSE.

Ms Blears insisted there was no risk to health from the vaccines after an extensive scientific inquiry but the news comes at the worst possible time for the Government.

There is growing concern over possible health risks associated with MMR and increasing numbers of parents are refusing to allow their children to have the inoculation.

Deborah Ryding, anti-MMR campaigner and founder of the Desumo single jab clinic in Herefordshire, said the news further undermined the Government's credibility.

She said: "They obviously did not look hard enough at the polio vaccine. It makes you wonder whether they have done so with MMR and other immunisations.

"It does not surprise me they could get it so wrong, it would not be the first time. I think parents will be very angry. A big error like this will raise a lot of questions."

Assurances about the safety of the polio vaccines came seven months after two people developed CJD, the human form of mad cow disease, after receiving the jab.

The cases in Southampton involved people given the vaccine derived from cow material in 1994.

Fears were first raised about the polio vaccine when an oral dose was withdrawn in October 2000 and an inquiry ordered.

Ms Blears said it was clear Ministers made a series of inaccurate statements to Parliament because of wrong advice from the Medicines Control Agency - MCA - which licences medicines and monitors safety. These included:

Contrary to earlier MCA advice, the guidelines have never entirely ruled out using UK-derived bovine material in vaccines.

It has emerged that not all licence holders could demonstrate that their products complied with guidelines on the use of bovine material.

Dates for switching away from UK-derived bovine materials were wrong and so were expiry dates given for some vaccines.

Statements said bovine-derived excipients were not used to make vaccines. In fact these substances, which can be derived from bovine materials, are sometimes used in finished vaccines.

Ms Blears said experts' investigations concluded that vaccines did not pose any BSE risk.

New European vaccine guidelines come into effect this summer and the Minister said checks had been carried out on all 95 used in the UK and there were no BSE risks with any of them.

'Keep taking vitamins' plea PEOPLE should not stop taking vitamin supplements in the light of research which claims they are unable to prevent heart disease, nutritionists said yesterday.

Dr Juliet Gray, a consultant nutritionist with the Health Supplements Information Service, said:

"You have got to have a balanced diet and antioxidant supplements are just part of that, to contribute to the reduction of damage by free radicals.

"They may contribute to the long-term prevention - over 30 to 40 years - of heart disease, cancers and eye disease."