Government officials were made aware of some problems with a version of the MMR vaccine in other countries but still introduced it in Britain in the late 1980s, newly released documents show.

The MMR vaccine with the Urabe strain of mumps was first used in Britain in October 1988. It was blamed for the deaths of several children after being withdrawn by the Department of Health in September 1992.

Previously confidential documents released under the Freedom of Information Act show how officials gradually learned of the dangers of the Urabe strain MMR which caused encephalitis-type conditions, including meningitis. Involving swelling of the brain or of the lining of the brain or spinal chord, they can lead to brain damage, deafness or even death.

The papers show that many months before the Urabe MMR vaccine was introduced in the UK, officials were made aware of problems in America, Sweden and Canada.

The first warning came when an unnamed official at a meeting of the Government's Joint Committee of Vaccination and Immunisation in May 1987 "expressed his reservations concerning reported adverse reactions to MMR in the USA".

The second came in a letter from the Central Microbiological Laboratory in Sweden in September that year, where authorities reported "52 cases of febrile convulsions probably associated with MMR vaccination".

Then, a Government working party on the introduction of the measles, mumps and rubella vaccine, learned of "a report of cases of mumps encephalitis'' in Canada at a meeting in Feb 1988.

The documents show that the statistical risk from Urabe MMR was considered to be low. The UK went ahead with its nationwide MMR programme in October 1988 in which 85 per cent of the triple-vaccinations contained Urabe.

The minutes of another meeting of the Joint Committee on Vaccination and Immunisation, in May 1990, show that there was "especial concern'' about "reports from Japan of a high level of meningoencephalitis associated with the administration of MMR".

The Government waited another two years before it decided to stop using Urabe MMR in 1992, after the manufacturers told officials that they would stop making it.

It was replaced with MMR II, which has a different mumps component. The minutes were obtained by the FOIA Centre, a specialist research company, on behalf of one of the parents of a child in a group bringing litigation at the High Court. The Government insists it acted swiftly as soon as it became aware of the dangers of Urabe MMR in September 1992.

Sir Liam Donaldson, the chief medical officer, told one of the parents in a letter: "As soon as the Department of Health had clear evidence that there was a risk with Urabe-containing MMR and that there was no such associated risk with a different strain of mumps virus (the Jeryl Lynn strain) used in an alternative MMR vaccine, the department moved quickly to discontinue use."

Prof Kent Woods, chief executive officer of the Medicines and Healthcare products Regulatory Agency, confirmed that the UK authorities had been aware of "sporadic cases" in Canada. However, the risk of meningoencephalitis from Urabe MMR was lower than the risk of the same condition resulting from "wild-type mumps virus", he said.

Urabe MMR was withdrawn "following reports of generally mild transient meningitis caused by the mumps vaccine virus in some children who recently received the Urabe mumps vaccine containing products".

Norman Lamb, a Liberal Democrat MP, said he would be pressing the Department of Health to find out why the warnings were dismissed.

A Government spokesman said: "The UK investigated the evidence and acted promptly when this problem with Urabe strain of mumps vaccine was identified.

"On the basis of information obtained in studies, the UK was in a position to make an informed decision on whether to continue using the Urabe vaccine, as there was an alternative vaccine strain, called Jeryl Lynn, which did not appear to have the same risk.''

The spokesman added: "In 1992 the Committee on Safety of Medicine considered all of the evidence and concluded that the benefits of vaccinating with Urabe mumps strain vaccines still outweighed the risks."