The fire service has issued advice about the dangers of swimming in local waterways after soaring temperatures prompted hundreds of youngsters to risk injury and even death by cooling off in rivers and lakes.

About 30 teenagers were swimming, diving and playing on inflatables, at the Rivermill, in Eaton Socon, on Monday afternoon seemingly oblivious to the potential dangers.

St Neots mayor, Councillor Derek Giles, has “implored” youngsters not to swim at the Rivermill, which has strong currents due to the nearby weir.

“I understand that it is very tempting but the weir at this location makes swimming in the river downright dangerous. There are undercurrents, weeds and obstacles under the water to contend with and things can easily go wrong.”

Councillor Lesley Craig, chairman of Houghton and Wyton Parish Council, said youngsters had also been seen using inflatable dinghies without life jackets in rivers around the villages.

She said: “The number of young people who are jumping into the river from every and any available spot they can find is worrying. They are jumping off the banks, they are jumping into lakes, I was also told they had been trying to jump off Houghton Mill itself.”

Cllr Craig added: “People have been raising concerns about it to the parish council. It is an accident waiting to happen. Do their parents know what they are out there doing?”

A water safety campaign was launched by Cambridgeshire Fire and Rescue Service, in May, 2015, 11 months after 15-year-old Rony John, from Huntingdon, drowned in the river at Hartford on the first day of the school summer holidays.

The #RememberRony campaign is aimed at educating school children about water safety.

Kevin Napier, who is head of community fire safety, said while he understood the temptations, he urged people to keep the #RememberRony campaign in mind.

He said: “We don’t want to spoil people’s fun by telling them not to jump into rivers and lakes, but we do feel it is important to educate everyone and also for parents to speak to their children about the risk open water poses.

“It is also important that if you see someone in trouble in water that you know what to do. Call 999 immediately with clear details of your location and, if possible, send someone to the nearest road to flag down the emergency services when they arrive.

“You can find the nearest life ring or anything that could help them float, and if someone goes under the water, mark on the water’s edge the place they were last seen with something like a piece of clothing.”