At the latest clinic, in Edinburgh, pet owners can get advice on diet and exercise.

Owners will also be encouraged to bring their pets in for two-weekly check-ups at the Companion Care surgery.

The clinic is one of a growing number in Britain specifically for obese pets.

Annual slimming competitions for pets, the Pedigree Slimdown and the Hill's Nutrition Pet Slimmer of the Year, already attract almost 1,000 animals between them.

Taking it lying down: Some cats need more exercise

Vet Scott Sheyney believes the battle of the bulge in domestic animals has now become a major problem.

He said: "Obesity is now a matter of great concern among our pet population and it is much more serious than most owners think.

"Being overweight can lead to all sorts of problems including heart disease, arthritis and ligament damage so it is really unkind to allow our pets to pile on the pounds.

Mr Sheyney blames some owners for giving their pets too much food.

"Occasionally being overweight can be caused by a hormone imbalance, but mostly over-eating and a lack of exercise are at fault.

"It is essential that we as owners learn restraint - however beseeching the eyes, it's not Fido who's going to open the packet of ginger biscuits or chocolate drops, but his owner."