AS temperatures are set to soar to 30C, people are being warned not to dive into open water to cool off.

Cheshire firefighters have joined forces with the police to highlight the dangers of cold water shock and how it can affect even the most confident swimmers.

Steve McCormick, group manager of Cheshire Fire and Rescue Service, said: “The water may look calm on the surface, but there can be strong undercurrents that could pull even a strong swimmer under the water.

Knutsford Guardian: Call 999 if you see anyone in difficulty in the water, don't be tempted to jump in yourselfCall 999 if you see anyone in difficulty in the water, don't be tempted to jump in yourself

“There is also the risk of cold water shock. The water may feel warm on the surface, but just a few feet below the surface it can be icy cold, which can affect stamina and strength of swimmers, or shock the body into a cardiac arrest.

““I want to encourage parents to warn their children of the dangers of entering open water, to only swim in designated swimming areas and to follow simple water safety advice.”

Weeds and unknown objects can also pose serious dangers.

Drowning is amongst the leading causes of accidental death in the UK

Inspector Brian Green said: “Already this summer residents have contacted us to raise concerns after seeing people jumping off a bridge into the River Weaver in Frodsham.

“Thankfully, no one has come into serious difficulty this time, but I want to warn people that it is dangerous to swim in open water.

“We know people will be increasingly tempted with the warmer weather but we would urge you to think again. If you need to cool off, use swimming baths or a lido or join a local open water swimming club.

“We’re not trying to ruin your fun, we’re trying to keep you safe – we don’t want to be knocking at your family’s door with tragic news about a loved one.”

Anyone who sees somebody getting into difficulty in the water is urged to call emergency services on 999.

Do not attempt to enter the water yourself.

For more information visit cheshirefire.gov.uk/public-safety/campaigns/outdoor-safety/water-safety