All of Worcester's 68 GPs and 17 other paediatricians and health visitors signed the letter which was published in the local evening newspaper.

In the letter, they raise their fears that the city could be heading for an outbreak of measles, mumps or rubella, the illnesses covered by the controversial jab.

The city is home to the controversial single vaccine clinic that offered three single vaccinations as an alternative to the triple dose.

The clinic prompted a General Medical Council hearing last year.

Since it opened, the GPs say take-up rate for the MMR vaccination has fallen to dangerously low levels and they fear they will see more young victims of the particularly serious measles.

The GPs add that they think their patients have lost faith in the government over their handling of the controversy.

'Misguided campaign'

They say Prime Minister Tony Blair's refusal to say whether or not his baby son Leo had had the jab also had a detrimental effect on public confidence.

Their openness is likely to fuel the political row over the inoculation.

The GPs describe campaigners for single jabs instead of the triple vaccine as "well meaning but misguided" and warn that parents are putting their children in danger by not having the jab.

In some areas of Britain only 65% of toddlers are being immunised with MMR and cases of measles are rising.