Police have warned that they “won’t hesitate” to break a car window if there are reports of a dog left inside.
They said owners will not be able to get their pet back from the RSPCA until the question of a possible prosecution for neglect or cruelty has been resolved.
The warning comes following the hot summer, with temperatures set to rise further.
PCSO Lee Hurley said: “As the temperature in the region is set to rise above 30 degrees we have to think about how the heat is affecting our furry friends.
“A little-known fact about dogs is they can’t sweat. The few sweat glands that they do have are usually found on the pads of their paws. Those paws can be easily burned on hot concrete.”
PCSO Hurley said: “Thee only way your dog can expel heat is by panting. For long haired dogs the hot weather can be particularly dangerous.”
Sgt Neil Lavender, of the Beds, Cambs and Herts police dog unit, said: “Your dog will still need exercise and want to go out - but you should choose to do it early in the morning or in the late evening when the temperature has fallen.
“We are still observing dog walkers taking their best friends out in the midday sun. This is a dangerous thing to do and should be avoided. Being left in a car - even with the window open a bit - is a lethal situation for dogs and no responsible dog owner should ever do it. Please don’t leave your dog in the car”.
PCSO Hurley added: “Officers continue to attend vehicles where dogs have been left unattended - and regardless of how long for - we won’t hesitate to break a window to rescue an animal.
“Dogs rescued from cars will be handed into the care of the RSPCA and won’t be returned to the owner until the question of prosecuting the owner for neglect of the animal, or animal cruelty, has been resolved.”
He said: “If you see a dog trapped in a car, do not hesitate to call us to save the animal’s life.”