Dog owners have been warned to beware a "silent killer" that could endanger their pooches as the UK is set to reach 34C highs this week.
Parts of the South East, London and Wales could reach at least 27C, rising to a possible 34C on Friday, hotter than Portugal, Jamaica, Costa Rica, the Canary Islands and Cyprus.
Friday is also predicted to be the hottest day of the year so far, eclipsing the 27.5C set in mid-May at Heathrow. It could even be the hottest June day for the UK since records began if the mercury tops the 35.6C recorded in Southampton in 1976.
In light of the scorching temperatures, the RSPCA has advised dog owners in the capital against walking dogs in the heat, reports MyLondon.
The charity said to be particularly careful in places where there is little to no shade, such as beaches and fields, adding: "If in doubt, don't go out."
Esme Wheeler, an RSPCA dog welfare specialist, said: "The truth is walking dogs in hot weather can be a silent killer.
"While the majority would never leave our dogs in a car on a hot day, or even take our dogs for a really long walk in the heat, many people may still be putting their dogs at risk even on a short walk, or taking them to places such as fields and beaches with little or no shade.
"We have long-campaigned that dogs die in hot cars, but this year we’re highlighting that dogs die on hot walks, too. The message remains very simple – never leave a dog in a hot car because ‘not long’ is too long, and when it comes to walks, 'if in doubt, don’t go out.'"
Dr Dan O’Neill, associate professor companion animal epidemiology at the Royal Veterinary College, has also warned about the serious dangers of walking dogs in the heat.
He explained vets see dogs with a range of issues, saying: “Heat-related illness can lead to organ failure, brain damage and ultimately death.
"Most people know that dogs die in hot cars, but the reality is that more than 10 times as many dogs need veterinary treatment for heat-related illness following exercise as for being overheated in cars.
“It can take weeks for a dog to acclimatise to hot weather, so after a spell of cold weather, periods of hot weather can be particularly dangerous.”
Dog owners can provide a paddling pool and make frozen treats to keep their pets cool and entertained if they are worried about missing exercise during hot weather.
Meanwhile, animal charity The Blue Cross urged cat owners to be cautious when leaving windows open after a kitten fell three storeys and fractured a leg.
The warnings come as parts of the UK may see an official heatwave between today and Saturday, which is when at least three consecutive days have daily maximum temperatures meeting or exceeding the heatwave temperature threshold. The threshold varies by county.
The threshold for a heatwave is 25C for Wales, Scotland and south-west England, 27C for southern and eastern England, and 28C for London.
Brits have been told to expect "uncomfortable" nights when trying to sleep, with temperatures remaining in the low 20s in the evening.
And people looking to top up their tans, swim in open water or use public transport have been warned to be wary.
Craig Snell, a Met Office forecaster, said: "Very high UV levels are expected in the South this week, meaning people should really avoid being in the sun during the midday hours.
"Wearing sunglasses, a shirt, a hat and sunscreen are essential to protect the eyes and skin, and drinking lots of water is important - long exposure to the sun can be dangerous.
"People should avoid overdoing it. We all love the sunny weather, but being sensible can help you avoid a nasty sunburn."
Giving an outlook for Friday, the weather service forecast hot and sunny conditions, although cooler in the north with rain.
