Muslim parents are refusing to allow their children to take part in a nationwide flu vaccine drive after the Muslim Council of Britain ruled the treatment was forbidden by Islam.

Public health officials have raised concern over the number of Muslim children expected to be withdrawn from a major programme beginning in schools next month.

For the first time, every healthy child of primary school age in England will be offered a nasal spray vaccine to protect people of all ages from the virus.

But Muslim parents across the country have been told that the Fluenz spray is not permitted because it contains gelatine derived from pigs, which are considered unclean.

In some areas the “vast majority” of Muslim parents have vowed to withdraw their children from the programme, community leaders revealed.

Tonight the Royal Society for Public Health said the situation “added to the risk of major flu outbreaks” and urged the government to offer a halal alternative vaccine acceptable to Muslims.

Since 2013 the nasal spray vaccine has been gradually introduced to healthy children, beginning with youngsters in nursery school. An injectable alternative without gelatine does exist, but is only offered to children at higher risk.

The programme has resulted in a significant reduction in flu cases, and from August the Fluenz spray will be offered to every child between the ages of two and ten.