More than one in five puppies bought online die in months

The shocking figure comes as it was revealed that increasing numbers of people are going online to buy puppies – outlets often used by puppy farmers.

One in three puppy buyers in Sussex are turning to internet and newspaper adverts.

The Kennel Club has warned that the problem is likely to grow as the younger generation favour mail order pups and fashionable cross-breeds often bred irresponsibly.

Jenny Wells, manager of the RSPCA Brighton Animal Shelter at Patcham, said: “We got lots of enquiries from people who have bought puppies that have got sick. They take them to the vets but they usually die.

“There’s a lot of interbreeding going on with people churning out puppies in squalid conditions.

“People are a bit misguided. They go and meet someone at a motorway service station. You wouldn’t buy a second-hand car from a stranger somewhere like that so it is unwise to do so with a dog.

“The dogs get very sick with diarrhoea and it’s very hard to help them, and it’s very contagious.

“It’s increasing with the internet becoming more popular.”

Anyone who breeds more than five litters a year needs a licence – but many puppy farmers are under the radar.

Hundreds of puppies are available to buy online from Sussex addresses from websites including Gumtree, Friday-Ad, e-Pupz and Pets4Homes.

Many posts advertise puppies from licensed breeders but selling is largely unregulated and an easy way for puppy farmers to profit.

New guidelines have been suggested by animal groups aimed at preventing unfair online ads for pets.

The Pet Advertising Advisory Group (PAAG) has put together a list of minimum standards for websites.

It is hoped the new advice will protect the welfare of pets being sold on the internet and help people to make safer choices when buying animals online.

It is estimated up to 3,000 pet adverts appear on UK websites every day.

A team of volunteer moderators will be working with websites to monitor suspicious adverts.