As another hot, dry day saw hospital chiefs up their state of alert to Level 3 – Heatwave Action – police were keen to stress the need for care around water, with children seen risking life and limb cooling off in the many water courses in the area.

And with the smell of barbecues filling the air on a daily basis, there are fears people might be tempted to get behind the wheel after drinking and dining al fresco.

Casualty reduction officer Pc Tony Barrios said: “As the weather warms up there is bound to be an increase in the number of people going out and drinking.

“Anyone doing so and planning on driving has a responsibility to themselves and other road users to ensure they do not drive over the limit.

“Our message is clear – if you drive under the influence of drink and drugs, expect to be caught and brought to justice.”

Orton Mere and Whittlesey Dyke have both become regular haunts for groups having fun in the water, unaware of the dangers lurking below.

A police spokesman said: “There are a few locations around the county where we are getting reports of people jumping into lakes or reservoirs on the hot days. People are risking their lives by doing this.

“Some people jump or dive into cloudy water not knowing what dangers lie beneath the surface.

“Please don’t risk your safety for the sake of cooling off on a hot day, as it’s simply not worth it.”

These warnings were echoed by the Royal Society for the Prevention of Accidents (ROSPA), with spokesman Carl Christopher saying: “We know people just want to have fun and cool down, but we urge people to really think through the risks before they enter any water.

“Parents should also remember to supervise their children, particularly under-fives, at all times, as, tragically, drowning is usually quick and quiet.”

With the city facing yet more sweltering temperatures – the Met Office is predicting daytime temperatures reaching a whopping 30C – those aged over 75, the very young and those with ill health have been warned to stay out of the sun, with health services on the second highest state of alert.

Assistant director of health improvement at NHS Peterborough Sue Mitchell said: “We want the public to take this heat warning very seriously, as heatstroke can develop if heat exhaustion is left untreated, but can also occur suddenly and without warning.

“Stick to the simple tips of keeping out of the sun when its at it’s hottest, stick to the shade, drink lots of fluid and look after those who are more vulnerable, such as children and babies as well as older friends and relatives.”

The last major heatwave to hit Britain was in 2003, when 2,000 people died, and NHS Peterborough has reminded people if they need medical attention, they must ring 999 in an emergency.