ore than three-quarters of the population believe there should be a full public inquiry into the combined measles, mumps and rubella vaccine, according to a recent survey.

Some 76 per cent of the 1,001 people surveyed believe the facts about the controversial MMR jab, which has been blamed for a rise in autism and bowel disease in children, should be made public.

The ICM poll for the News of the World found that the number of parents who believe the jab is safe has fallen since the same question was asked last year.

Asked if they believed MMR was safe, 55 per cent said they did - down 11 per cent since August 2001 - 28 per cent said they were unsure while 17 per cent believed it was dangerous.

Parents' groups advocating the use of single, separate vaccines welcomed the results.

Debbie Ryding, of Desumo Information & Healthcare Ltd, said: "I think most of the parents that come to us would be behind that.

"I certainly think it needs looking at. We have been asking as parents for long enough about these issues."

Mother-of-six Mrs Ryding, from Ledbury, Herefordshire, set up the organisation with Natalie Bowden, who has three children and lives in Swansea, to raise awareness about choices available in vaccination.

They operate a clinic in Worcester using the services of a Lincolnshire GP, Dr Peter Mansfield, and are setting up centres in Bournemouth and Swansea.

Mrs Ryding said the numbers of parents with concerns about MMR and other childhood vaccinations were growing.

She added: "It seems that the more the Government tries to impose the MMR on parents with things like talk of it being compulsory, parents dig in their heels more.

"Just going by our figures, it really has grown so big so fast. You just can't keep up with the amount of parents who want information and single vaccines for their children."

MMR is given to children at aged 13 months and before they start school.

It was first introduced in the UK in 1988 and has since seen the number of children catching the diseases it protects against drop to an all-time low, according to Government figures.

The Department of Health accepts that children who have been immunised with MMR do sometimes experience side-effects but said it is usually mild forms of measles, mumps or rubella.

Incidences of severe allergic reactions immediately after immunisation are "very rare", occurring in about one in 100,000 MMR jabs, and prompt treatment should lead to a full recovery, the DoH added.

Officials have rejected a causal link between MMR and other measles vaccines with autism and inflammatory bowel disease and said the suggestion has come mainly from one source, a team led by Dr Andrew Wakefield at the Royal Free Hospital in London.

Higher diagnoses of autism have occurred because of greater awareness of the condition, they said.

The Government has said it takes "extremely seriously" any concerns raised about the safety of medicines and vaccinations.

All claims and allegations have been referred to the Joint Committee on Vaccination and Immunisation (JCVI) and the Committee on Safety of Medicines (CSM) for "thorough investigation", using research from around the world.

"On all the evidence available, the JCVI and CSM have agreed that there is no link between MMR and autism. This view is supported by experts from around the world, including the World Health Organisation," the DoH website states.

It insists there is also no scientific evidence to support giving three separate vaccines at different intervals and that children could be put at risk in the meantime.

A DoH spokesman reiterated the position: "MMR has been reviewed endlessly by international expert groups worldwide, including a recent report to the Scottish Parliament.

"All these reviews are available to the public. The UK Joint Committee on Vaccination and Immunisation, an independent experts group, has reviewed every piece of evidence as it emerges.

The view remains that on the scientific evidence, there is no causal link between MMR, bowel disease or autism," he said.