A 21lb cat is taking part in the UK's biggest pet slimming contest.

Pompom the cat doubled in size due to an all-day buffet lifestyle and lack of exercise.

Following a visit from PDSA vets, eight-year-old Pompom was place on a diet by his owner Joanna Klosowska.

She hopes that Pompom, who tips the scales at 21lb 5oz, will win a place on PDSA’s pet fit club competition, the UK’s biggest pet slimming contest.

Joanne said: “I’ve had Pompom since he was three-months-old but he put on the weight because my husband was feeding him. He was buying food that was too high in fat from the market and he had access to dry food even at night time.

“Because Pompom is a house cat he also doesn’t get much exercise, but we’re trying to get him more active. He has to walk for his dry food from one room to the other and I hope it will help him to be slim before spring time.”

PDSA asks the UK’s most overweight pets to enrol in a six month diet and exercise challenge.

It warns owners should not overfeed them especially if they do not get enough exercise.

PDSA vet Olivia Anderson-Nathan said: “Prevention is always better than cure, but it is never too late make a change. With the right advice, a good diet, suitable exercise and a bit of willpower owners have the ability to make a real difference to their pet’s lives.”

The closing date for the PDSA challenge is March 3. To apply go to pdsa.org.uk/ petfitclub .