THE underground puppy trade is on the increase, the RSPCA has found, with more calls than ever before reporting questionable breeders and dealers.

The animal welfare charity saw its busiest year tackling the issue in 2016, dealing with 132 per cent more complaints than five years before.

New figures have revealed England’s puppy farming hotspots with London coming out on top with 280 calls about the puppy trade.

Last year in Dorset, the charity received 42 calls.

Working alongside online marketplace Gumtree, the RSPCA also looked into the areas with the highest number of online listings advertising dogs and puppies for sale.

There were 1,929 in Dorset in 2016, making it 26th in England for number of listings.

Lisa Richards, RSPCA dog welfare expert, is urging people to be “extremely careful” when choosing where and who to buy a dog from.

“It’s so important to do lots of research, not only into the type of dog you want and the kind of care he needs, but also into any potential breeder that you’re considering going to.

“Today, particularly with the rise of puppies being advertised and sold online, it’s becoming more and more difficult to tell the responsible breeders apart from the unscrupulous ones.

“We would encourage anyone who is thinking of getting a puppy to use the Puppy Contract to help ensure they buy a happy, healthy dog.”

RSPCA stings on organised puppy selling networks have uncovered criminal gangs making up to £35,000 a week by selling dozens of puppies - often fashionable breeds and designer crossbreeds. And the charity has rescued more than 1,200 from puppy farms across the country in the past four years - but knows this is just the tip of the iceberg.