A warning has been issued urging people not to swim in rivers, canals and lakes in an attempt to cool off during the heatwave.
It follows two deaths in a water-filled quarry in Norfolk on Tuesday.
Jess James, station commander at Caversham Road fire station where the Royal Berkshire Fire and Rescue Service's Water Rescue Unit is based, said: “It may be very tempting to cool off in rivers, ponds or lakes when the weather is so hot but there are just too many potential dangers.
“It is impossible to know what may be beneath the surface of the water. Discarded shopping trolleys and rubbish such as broken glass are a real hazard, as are unseen currents and reeds, which can affect even the strongest swimmers. We strongly urge people not to take the risk.”
He added that while the surface of the water may feel fairly warm, underwater temperatures will be unaffected by the sun and will remain bitterly cold.
This can make swimmers’ muscles tire very quickly and can cause severe cramp, muscle spasms and shock. Drinking alcohol can make things even worse, as people may overestimate their swimming abilities and fail to notice potential hazards.
During the summer, water levels can also be deceptively low and, although rivers and lakes may appear deep enough, jumping or diving into them can cause serious injuries, paralysis or even death.
Open water is home to many organisms that can cause serious illness if swallowed or enter via a break in the skin.
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