With temperatures set to soar this week, visitors to Grafham Water have been urged not to put themselves at risk by taking a dip in the reservoir.

Anglian Water issued the warning after reopening the reservoir after lockdown.

David Hartley, from Anglian Water, said: “Even more than usual this year, with the current measures in place around social distancing and the added pressures on our emergency services, we are urging people not to put themselves at unnecessary risk.

“Swimming in reservoirs and watercourses can pose a risk to life for anyone. Strong currents in the water and hidden machinery often lie just below the surface, as well as mud and weeds which can trap swimmers. The unexpectedly cold temperatures in large bodies of open water can also cause cold water shock, resulting in involuntary inhalation of water, often tragically resulting in drowning.”

Some facilities at Anglian Water’s reservoirs remain closed, including the beach at Rutland and all organised events are currently postponed, meaning swimming in the reservoirs is illegal.

Mr Hartley added: “Although it might seem appealing to dive into the cool water on a hot day, they are operational sites, and can be extremely dangerous for even the strongest swimmer.”

Met Office chief meteorologist, Dan Suri said: “Northern Ireland and Scotland will be under a band of cloud and rain on Monday and Tuesday, however it’ll be dry elsewhere with plenty of warm sunshine and temperatures reaching 28 or 29 Celsius in a few spots on Tuesday.

“Temperatures will continue to climb through the week with a hot spell developing across much of England and Wales. From Wednesday temperatures will widely reach into the high twenties Celsius and it’ll be hot across much of the UK, especially central and southern England where we could see highs of 30 to 34 Celsius. This hot weather is expected to last until at least Friday and so heatwave conditions are likely to develop for some areas this week.”

“In addition to the warm days we are going to see some warm nights this week as temperatures overnight remain in the mid-high teens across England and Wales.”