The Royal Society for the Prevention of Cruelty to Animals (RSPCA) has urged pet owners not to leave their dogs in hot cars as temperatures soar.
Met Office forecasters have predicted highs of up to 32 degrees C will be recorded in areas of the UK.
Dogs left in cars at this temperature are at risk of developing health problems, or even dying if exposed to the heat for even a short amount of time, according to the foundation.
The charity said many canine owners think if the air conditioning is on when they leave their vehicle, its cool climate will be maintained and the pet will be safe.
However, this isn’t the case and even five minutes after the engine is switched off temperatures can rise to the same level as outside the car.
RSPCA animal centre manager Darren Parrish said: “With the changeable weather recently people may have been even more forgetful than usual about how hazardous the inside of a vehicle may be for an animal.”
Symptoms of overheating in dogs include a lack of co-ordination, collapsing, vomiting, diarrhoea, purple gums and a rapid pulse.