AN expert on autism has been criticised by campaigners for saying new research has been unable to find a link between the condition and the MMR jab.

In a wide-ranging discussion at the International Science Festival in Edinburgh last night, consultant in paediatric neuro-disability, Dr Paul Gringas, said about 30% of children with autism would develop normally for a period and then show signs of a condition known as regressive autism.

He said: "It is extremely understandable that we are going to look at whatever was being used by the child at the time and the MMR jab is normally given at 13 months.

"But autistic regression has been well described for at least 20 years before MMR was ever used."

During the wide ranging discussion, Dr Gringas said there had been a steady global rise of autism over the past 30 years, with one in every 175 children now affected.

But the expert from Harper House Children's Services in Hertfordshire said he believed the rise was down to more efficient diagnosis and a broader definition of autism.

Science in detecting the condition had improved, he said.

He cited research which showed abnormal head or brain growth early after birth was detected in 90% of autism cases, while further studies had picked up early signs of the condition in children as young as one year old.

Although dubious about the MMR link, Dr Gringas, addressing an audience of about 100 parents, experts and other interested parties, said there appeared to be a connection between bowel problems and the condition.

He said: "Bowel problems are more common in children with autism but the rate of these problems are no higher between children who received the vaccine and those that didn't."

But protesters who argue that there is a link between the vaccine for measles, mumps and rubella and autism, said his presentation had been "one-sided".