Just over half (55.5%) primary school children - around 2.5m out of a total of the 4.5m eligible – received the vaccination last year.

The low take up was mirrored by a drop in uptake of all routine childhood vaccinations.

Dr Suzanna McDonald, flu programme lead at the UKHSA said: ‘Younger children are at higher risk of developing complications from flu and being hospitalised. Ensuring children are vaccinated against flu with a painless and easy nose spray, not only helps to protect them, but also helps stop them spreading it into the wider community and to those who may be even more vulnerable, such as younger siblings and grandparents.

‘That is why we are so concerned that flu vaccine uptake among children in primary schools is too low and many thousands of children are unprotected. It's vital we turn this around. This will take a concerted effort – with parents returning consent forms in good time; and our school vaccinations teams and head teachers working together to deliver the vaccine programme – helping protect children and give them the best start to thrive in school.'

Children's flu vaccinations will start in some schools from this week and local immunisation teams will move from school to school across their region with all schools expected to have been offered sessions by late November.