The government's top doctor has criticised the man at the centre of the MMR controversy.
Sir Liam says the MMR jab is safe
Sir Liam Donaldson, England's chief medical officer, accused Dr Andrew Wakefield of peddling "poor science".
He said the 1998 study was flawed and has been criticised by "independent experts around the world".
His comments came as the General Medical Council prepared to open an investigation into the way Dr Wakefield carried out his study.
Meanwhile, Prime Minister Tony Blair has urged parents to have their children vaccinated.
"There's absolutely no evidence to support this link between MMR and autism," he said.
"I hope now that people see that the situation is somewhat different to what they were led to believe, they will have the triple jab because it is important to do it."
On Friday, the medical journal The Lancet said it should never have published Dr Wakefield's study.
Dr Richard Horton, the journal's editor, said the work was "flawed" because Dr Wakefield had "a fatal conflict of interest".
On Saturday, Health Secretary John Reid urged the GMC to investigate "as a matter of urgency".
A spokeswoman for the GMC said: "We are concerned by the allegations and will be looking to see what action, if any, may be necessary."
Dr Wakefield's paper prompted many parents to reject the three-in-one jab, even though most experts say it is safe.
"If the paper had never been published, then we wouldn't have had the controversy, we wouldn't have had the seed of doubts sown in parents minds which has caused a completely false loss of confidence in a vaccine that has saved millions of children's lives around the world," said Sir Liam.
The Lancet says it was never told that Dr Wakefield was carrying out another study at the time of his controversial research.
Dr Wakefield was funded to see if there was any evidence to support possible legal action by a group of parents who claimed their children were damaged by the vaccine. Some children were involved in both studies.
Dr Wakefield denies receiving any direct payment, and said funds were given instead to the hospital at which he worked, London's Royal Free.
He insists he has done nothing wrong and says the science behind his study still stands.
He welcomed the GMC investigation. "I not only welcome this, I insist on it," he said.
"Serious allegations have been made against me in relation to the provision of clinical care for children with autism and bowel disease, and the subsequent reporting of their disease."
Jackie Fletcher of JABS, a group which is against the three-in-one jab, backed Dr Wakefield.
"Dr Wakefield's original data is not in question at all," she said.