Fewer Scottish toddlers are being immunised with the controversial MMR vaccine, according to new figures.

Statistics showed that 13% of Scottish two-year-olds had not received the measles, mumps and rubella jab.

And the trend has sparked a warning to parents from Scotland's chief medical officer, Dr Mac Armstrong.

He said that those who had not immunised their children were running "high risks".

But campaigners have warned that the trend will continue unless there is a change in policy to allow single vaccinations.

The injection has been at the centre of controversy over fears that it could be linked to autism in children.

Earlier this year a report by the Scottish Parliament's health committee concluded that there was no reason to doubt its safety.

Its members said that, on the current evidence, there was no scientific link between autism and the triple vaccine - but also acknowledged that there were still many unanswered concerns.

MSPs called for the creation of an expert committee to carry out further research into the vaccine.

The latest figures showed that the number of Scottish two-year-olds receiving the jab had fallen by 3% since March to 87.8%.

Dr Armstrong said the figures were "disappointing but not surprising".

"This trend now means that 13% of children in this group are not protected against three serious diseases," he said.

"We are now running high risks for children who are unprotected and those most vulnerable around them - such as children with chronic underlying conditions who cannot be immunised for clinical reasons."

He said new information packs on MMR would be sent out to family health professionals.

"These will explain the background to the present programme, address parents' concerns, and explain that MMR remains the best way of protecting all of our children from the dangers of these diseases," he said.

"I must reiterate the risks we run when claims of new and untried theories threaten the health of our children.

"The evidence overwhelmingly favours MMR vaccine as a safe and effective means of protection."

However, Action Against Autism chairman Bill Welsh said legitimate calls for children to be offered single vaccines were being ignored.

"Parents are voting with their feet," he told BBC News Online Scotland.

"They know that the MMR or nothing policy is an insult and totally unsupportable.

"The uptake of MMR will continue to fall until the cause of autism is identified and the present epidemic explained.

"The current vaccination policy will result in the worst of both worlds - a continuing autism epidemic and a measles epidemic.