One third of 11-year-olds leaving primary school do so unable to swim, according to research by the Amateur Swimming Association (ASA).
According to the ASA, 200,000 children leave school each year unable to swim, despite swimming lessons being part of the national curriculum.
The ASA says that this could lead to there being two million children unable to swim in the next decade, if no stronger action is taken.
The Department for Education rules that children shopuld be able to swim 25m unaided by the time they move on to secondary school.
However, the ASA's Save School Swimming, Save Lives report also found that nearly 40% of those that are not able to swim were never offered lessons by their school.
"By not teaching children to swim, we are putting their lives in danger," John Glenn, head of youth and community at the ASA said.
The report claims that more than 400 British deaths per year are a result of drowning and is the third highest cause of accidental deaths of children.
“Swimming is the only subject on the national curriculum that can save your life,” the chief executive of the ASA, David Sparkes, said.
“It’s essential that government, schools and parents join us in taking action and break the cycle before we create a generation of non-swimmers unable to pass on this life-saving skill to their children in the future.”
One common cause of children not being offered lessons was lack of funding available to local authorities as a result of budget cuts.
According to Sport England, a total of 23 pools were shut by local authorities, as well as 12 schools across the country.
Following the report, the ASA and Kellogg’s, who contributed to the research, will meet with the government on Thursday to urge all relevant organisations to prioritise swimming lessons in the curriculum, allowing all children to learn regardless of background.
Watch the ASA's video for their campaign on the importance of swimming lessons below: