If the public health doctors have done their work, then we can all sleep in our beds, but at the moment, there is doubt

Dr Andrew Wakefield

Dr Wakefield's paper is a review of all the safety checks carried out on MMR prior to it gaining a licence in the UK.

Most checked a number of patients for signs of adverse reactions to the vaccine in the weeks following the injection.

However, Dr Wakefield found that the longest any of these checks looked only four weeks after the jab, and many covered even shorter periods.

He told the BBC that he felt the evidence for a link between autism and MMR was "stacking up"

He said the original trials had been flawed.

Parents deserve choice

"They had not been conducted for long enough to establish or exclude the possibility of delayed adverse effects beyond four weeks.

"There were clues in there that there were problems, including the gut, and these were not followed through."

"If the public health doctors have done their work, then we can all sleep in our beds, but at the moment, there is doubt, and where there is doubt, further investigation is required," he said.

The MMR is generally given on two occasions

"And until that time, then the parents absolutely deserve the choice of vaccines - substituting the single vaccines for MMR."

Dr Wakefield's original papers describing a possible link between MMR and bowel disease, or autism, caused a storm and led to thousands of parents refusing to have their children immunised in this way.

The government maintains that MMR is a safe vaccine, saying large scale studies have failed to find a link between either illness and the jab.

It is worried that the drop in immunisation rates may leave many children vulnerable to any of the three infections, which can have disabling or even fatal consequences in a very few cases.

This research is simply going to scare people into thinking that MMR is not safe.

Dr Simon Fradd, Doctor Patient Partnership

Dr Peter Fletcher, who used to assess the safety of medicines for the Department of Health, told BBC News Online that Dr Wakefield's research paper did not contain any extra evidence to alarm parents, but that this would be the inevitable effect.

He said: "Parents should definitely continue to have their children immunised against these illnesses.

"But this study certainly won't diminish their concern about this vaccine."

He said that the brevity of the initial studies had been a "missed opportunity", and that extending them over a longer period could have provided far more data on the safety of the vaccine.

It is argued that the combined jab is easier on children

Dr Simon Fradd, chairman of the Doctor Patient Partnership, said that it was vitally important that parents continued to allow their children to have MMR.

He said: "This research is simply going to scare people into thinking that MMR is not safe.

"The paper leads to the conclusion that the original research on MMR is invalid, but this happened many many years ago.

"Since then there have been millions of doses of MMR given, which gives you a much clearer idea of whether the vaccine is safe or not."