Dinner would often end up in Co-Co the dog - along with pigs ears, pizza and anything else left within paws' reach.

The chocolate-coloured Labrador enjoyed such a pampered lifestyle she eventually tipped the scales at more than ten stone.

She would get out of breath after a few minutes walking and waddle around with black Labrador sister Holly, also a portly pooch.

But now the pair, both aged five, have been shedding the pounds and are looking forward to a healthier future.

Jackie Friend, 55, of South Terrace, Littlehampton, who owns the dogs, said: "If you stood still long enough, Co-Co would eat your leg.

"Her weight problem was all my fault. If I had my dinner and there was anything left over, they would be given it.

"I also gave them lots of treats like pig's ears. I never gave them chocolate, though."

Jackie, who works in a laboratory for the Government's Department of the Environment, Food and Rural Affairs, said: "Holly was a little overweight but not as bad as Co-Co, who would eat anything. If you put something down for her it would just disappear."

Jackie, who has one son and bought the dogs as puppies following the death of her husband five years ago, took the pair to Pet Doctors in Rustington, where vet David Hodges was appalled by the barrel-bellied canines.

She said: "They had to go in for their booster injections. David looked at them and then me and I said: 'I know they are very overweight, Co-Co especially, and it's all my fault'. I couldn't blame anyone else, I'd been spoiling them."

David said: "Through genuine love and affection, pet owners have no idea just what harm they are putting their pets to with treats and special dinners.

"Obesity in a cat or dog can cause or worsen a range of conditions including arthritis, heart disease, diabetes mellitus and intolerance to heat.

"And it's not just cats and dogs. Many are surprised to know that rabbits and even tortoises can suffer from obesity."

Signs to look out for in tubby pets include stomachs which tend to sag and bulge sideways, difficulty in feeling their ribs, reluctance to walk and a shortness of breath.

To get the pair fit, David put them on the Hill's Science Plan slimmer programme and ordered the dogs to take more exercise.

Within a year, Co-Co has shed almost four stone, leaving her a svelte six stones, and earned herself a place in the quarter finals of the Hill's Pet Slimmer of the Year competition, which is a national contest open to all pets.

Jackie will be travelling to Kent on November 20 for the next round of the competition.

Holly has lost a stone on the same diet. She previously weighed 5st 11lb, she now weighs 4st 11lb.

Since shedding the weight, Co-Co has a new lease of life.

Jackie said: "She's very lively now but she's still trying to get as much food as she can.

"A friend brought two pizzas over last week and left one on the side in the kitchen. We put one in the oven and one on the side. When we went in there, the second one had disappeared. We looked everywhere for it and realised she had eaten the lot.

"She can jump up now and must have jumped up, put her head sideways and grabbed it."

If Co-Co wins her regional heat and gets through to the national final, she and Jackie could win £500 worth of pet accessories, a year's supply of Hill's food and £2,000 worth of holiday vouchers.