Children at private schools face the greatest risk from the measles outbreak and could pose a health threat to the rest of the population, a leading doctor has warned.
Professor John Ashton said Britain's 600,000 privately-educated children were at much greater risk of infection than those in the state sector.
Prof Ashton, who represents the UK's public health doctors, said a mix of large numbers of middle-class children who were not vaccinated against measles following the Wakefield scare in the 1990s, along with pupils from overseas with unknown health records, meant schools could become "reservoirs of disease", the Daily Telegraph said.
He said the risk was similar to that from groups such as gypsies and travellers, who have previously spread the disease.
Prof Ashton, who will soon become president of the Faculty of Public Health, said: "You've got a lot of middle-class, well-off parents, large numbers of whom did not have their children immunised because of the Wakefield scare - which was a very middle-class phenomenon.
"Layered on top of that you have got a lot of children from abroad, especially from the Far East, from countries such as Hong Kong and China, and there are few checks being done to establish their immunisation records."
He said private schools were a "law unto themselves", and warned both pupils and the wider population were being put at risk from infectious diseases because the schools do not have proper policies to protect children and are bad at keeping adequate medical records of pupils from abroad.
Prof Ashton said: "The danger is that you have a population that can potentially become a reservoir of infection.
"Normally when you are talking about subsections of the population that are at particular risk of disease outbreaks, such as measles, you are talking about groups like gypsies and travellers.
"But actually children in private schools, and in particular boarding schools, are one of the categories most at risk."
He urged independent schools to check immunisation records of overseas pupils as a matter of urgency, and advised them to "engage with" families who refused to vaccinate their children.
Dr David Elliman, an immunisation specialist from the Royal College of Paediatrics and Child Health, said he believed there was a high chance that an outbreak of measles would occur at an independent school, saying health officials were braced for such a crisis, the Telegraph said.
Prof Ashton's warning comes as health chiefs launched a major in-school vaccination drive across three counties neighbouring a region battling a measles epidemic.
Thousands of unprotected children are being targeted as part of an exhaustive four week programme to stop the disease spreading in South Wales.
The number of measles sufferers in the greater Swansea area looks certain to pass the 1,000 mark over the weekend.
Four local hospitals will host drop-in vaccination clinics today, for the fourth consecutive Saturday.
Vital vaccination sessions will also continue in a number of Swansea and Neath and Port Talbot schools next week.
A parallel programme is now being rolled out across three counties to the west of Swansea.
It comes as a major £20 million vaccination programme was announced in England targeting one million unprotected children and teenagers.