The government has warned Britain could face a measles epidemic after a big drop in parents taking their children to GP surgeries to get the MMR vaccination.
Health minister Dawn Primarolo said there has been a rise in the number of measles cases in children under 18 in England as a result of "a decade of relatively low measles, mumps and rubella vaccination uptake".
A similar warning has been made by the Health Protection Agency after it reported 1,049 cases of the contagious disease in England and Wales during the first 10 months of last year, the highest since a new recording system was introduced in 1995.
In a Commons written reply, Ms Primarolo told Tory health spokesman Mike Penning: "The potential exposure of a large number of unprotected children to the measles virus means that there is a real risk of a large measles epidemic."
The increase has been blamed on an increase in the number of parents being put off by the jab after reports it could lead to autism.
In response to the growing threat the Department of Health has launched a "catchup campaign" with the aim of immunising all unvaccinated or partially vaccinated children below 18.