The government has launched a campaign to increase uptake of the MMR jab amid growing fears of a measles epidemic.

The Department of Health is making extra doses of the vaccine available and has asked NHS trusts in England to offer it to all children aged up to 18 who are not already fully protected against measles, mumps and rubella.

The chief medical officer for England, Professor Sir Liam Donaldson, has written to all local health trusts urging them to persuade parents to get their children immunised.

The number of cases of measles is on the rise across the country. There were 1,726 confirmed cases in England and Wales in 2006 and 2007 - more than in the previous 10 years put together, when there were 1,621 cases.

Estimates by the Department of Health suggest a measles epidemic in Britain could affect between 30,000 and 100,000 children and young people.

Uptake of the MMR jab fell to an all-time low after medical journal the Lancet publication a controversial and now discredited study that suggested

the triple vaccine was linked to autism and bowel disease. The lead author of the paper, Dr Andrew Wakefield, is currently appearing before the General Medical Council (GMC) on charges relating to the research.

MMR vaccination rates vary across England but remain particularly low in London. Trusts in the capital will receive an extra £60,000 in the campaign, while those outside London will get £30,000.

Estimates suggest around 3 million children and young people aged between 18 months and 18 years have missed either their first or second dose. After the first dose, between 5% and 10% of children are not yet protected. After two doses this falls below 1%.

The first injection is given at around 13 months of age, with a booster before starting school, usually between the ages of three and five.

Professor David Salisbury, the director of immunisation at the Department of Health, said: "Parents who have not had their children vaccinated with the MMR vaccine should do so now. The evidence on MMR is absolutely clear - there is no link between the vaccine and autism.

"The MMR vaccine coverage is not high enough to remove the threat of recurrence of measles outbreaks. Measles is serious and in some cases it can be fatal. Delaying immunisation puts children at risk."

Dr Patricia Hamilton, the president of the Royal College of Paediatrics and Child Health, said: "We cannot stress too strongly that all children and young people should have the MMR vaccine. Overwhelming scientific evidence shows that it is safe."

A joint report published this year by the Health Protection Agency, Guys hospital and Manchester University found no evidence of a link between the MMR vaccine and autism.