Researchers at Sunderland University questioned the parents of 4,000 sufferers of autism across the country.

Their results led them to believe at least 10% of the cases of autism were triggered by the controversial triple mumps, measles and rubella vaccine.

Most of the research has not been published and the team behind the study say more work is needed by other scientists.

During the study the researchers used an eight-page questionnaire to quiz the parents.

They also took urine samples and found those who had received the vaccine had different levels of a particular protein.

The study is at odds with a recent published review of previous research, which found no evidence that MMR is associated with autism.

Epidemic fears

Earlier this month, a team led by Dr Anna Donald and Dr Vivek Muthu produced research into MMR which they had gathered from 180 countries around the world.

Our advice remains that MMR is the best way to protect children against measles, mumps and rubella

Department of Health

They found no evidence to suggest MMR or single measles vaccines were associated with either autism or inflammatory bowel disease.

And just last week it was claimed that a controversial scientist alleging a link between the MMR vaccine and autism had failed to help officials verify his work.

Doctors in London are worried about the risk of a measles epidemic and there are concerns about the low numbers of children being given the MMR vaccine.

There were 16 new cases of measles in the capital in May alone.

More than 70% of children in London have been given the MMR jab, but the government target is 90%.

Experts say MMR can protect 90% of all children who have an initial vaccination, while a second dose raises the level of protection from measles to 99%.

Dr Paul Shattock, director of the Autism Research Unit at Sunderland University, said the evidence that MMR was linked to autism was strong - but not conclusive.

Claims dismissed

However, Dr Peter Dukes, research strategy manager at the Medical Research Council, said there was plenty of independent research to suggest that MMR was not linked to autism.

He told the BBC: "There is strong positive evidence of no link."

A spokesperson for the Department of Health stressed that the Sunderland research was still work in progress, and had not been vetted by other scientists.

"The British Medical Journal recently commissioned and published the most comprehensive review yet of all the epidemiological evidence in this area.

"This confirmed earlier studies that the scientific evidence finds no link between MMR and autism or inflammatory bowel disease.

Last December the Government pledged �2.5 million towards further research into the causes of autism.

"We will continue to keep all the evidence under review.

"Our advice remains that MMR is the best way to protect children against measles, mumps and rubella."