Britain could become a nation of non-swimmers if action is not taken to dramatically improve school access to facilities and lessons.

That is the stark warning from University of East Anglia academics, who today highlight research that 51pc of children aged seven to 11 are unable to swim 25m, despite it being a national curriculum requirement by the time they go to high school.

Researcher Craig Avieson said because swimming is not compulsory for ages 11-18, these children will become adults who cannot swim, and then parents who do not take their children swimming.

With secondary school teachers often left to pick up the pieces, a UEA pilot scheme to give trainee secondary school teachers greater confidence in teaching swimming, and helping the lowest-ability children, could hold the key to turning the situation around.

Dr Avieson, a qualified swimming instructor of 12 years who has also taught PE at Dereham Neatherd High School and Riverside Middle School in Mildenhall, said it was crucial swimming is prioritised when primary schools use an extra £150m of government money for sports, given each year until 2020.

He said the swimming crisis was most acute in rural areas, such as Norfolk and Suffolk, where small schools face the time and cost of transporting children to pools.

'We are not looking at blame. We are saying primary and secondary schools need to work together to use the new government funding for PE to support ways of addressing this. It needs to be everyone addressing it together', he said.

'We are optimistic that if people are aware of this research, then we can start to reduce this significant deficit of children who can't swim.'

He said schools could use the new money to pay for transport to swimming pools, train teachers, or help parents encourage children to swim in after-school clubs, summer schools or working with sports centres.