The study found no link between the MMR vaccine and autism

An international team looked at the incidence of autism among 31,426 children in a Japanese city before and after the jab was withdrawn in 1993.

It found autism rates kept rising after the MMR vaccine was withdrawn.

But Jackie Fletcher, of campaign group Jabs, called for research into hundreds of UK children affected by autism.

She said: "Instead of relying on research carried out abroad, we would like the government to actually clinically investigate the 1,700 children believed to have been affected by the MMR jab in the UK.

"We've all got the same objective of preventing infectious diseases. But we also want to prevent injury to children too."

These findings are resoundingly negative in relation to the link between MMR and autism Professor Michael Rutter, Institute of Psychiatry

It comes after Michael Rutter, of the Institute of Psychiatry, who worked on the study, said its findings "rubbished" the link between MMR and a general rise in autism.

Professor Rutter told the BBC News Website: "If there was a true causal relationship between MMR and autism, one would have expected rates to fall after the vaccine was withdrawn.

"In fact, the rate continued to rise."

He added: "These findings are resoundingly negative in relation to the link between MMR and autism. They rubbish the claim that MMR is having a general effect on the rate of autism."

He said the research did not deal with the suggestion that there is a small group of children who are unusually vulnerable in whom MMR triggers autism - but there was no evidence that this was the case.

Steady rise

However, Professor Rutter said there had certainly been a rise in autism cases.

"Professionals are better at picking it up. And there has been a broadening of the definition, so it's not just children with the most severe form of autism, but all gradients within the range of autistic disorders who are diagnosed."

Concern over the MMR vaccine were first raised in a study by Dr Andrew Wakefield published in the Lancet in 1998 which claimed it might trigger autism.

However, no research has ever proved a link, and the overwhelming majority of experts believe the vaccine is safe.

Despite this, rates of MMR vaccination in England have continued to fall. In some areas, they are just over 60%.

The latest study, carried out by the Institute of Psychiatry and Yokohama Rehabilitation Center is the first to look at rates of autism after the withdrawal of the vaccine.