Media playback is unsupported on your device Media caption Boris Johnson's new rescue puppy moves in to Downing Street

A puppy from an animal rescue charity in south Wales has moved into Downing Street with Prime Minister Boris Johnson.

The 15-week-old Jack Russell-cross, which has been named Dilyn, had been left abandoned by puppy farmers.

It has moved from Friends of Animals Wales in Rhondda, into the flat above No 11 Downing Street where Mr Johnson and his partner Carrie Symonds live.

They were keen to promote Lucy's Law - a crackdown on puppy farms.

A spokesman for the prime minister said: "The PM has always been a passionate supporter of animal welfare and believes in giving animals the best start in life."

The link between the couple and Friends of Animals Wales (FOAW) came through TV vet Marc Abraham who has worked with the charity's owner Eileen Jones.

"It was important to shine a light on the work she's doing," he said.

Image copyright Parsons Media Image caption Dilyn arrived at Downing Street on Monday

"It's entirely voluntary with huge vets bills so they only rescue and rehabilitate the ones with the most problems.

"When I was speaking to Carrie about what dog to get and where to get it from, she gets it. She is a massive supporter of the Lucy's Law campaign.

"Carrie and Boris are helping to get a very, very vulnerable dog that's otherwise likely to be killed.

"They are both massive dog lovers."

Ms Symonds tweeted: "Thanks to the wonderful Eileen who rescued Dilyn after she got a tip-off that he was to be dumped by a puppy dealer because he was born with a crooked jaw.

"Eileen fixed his little jaw and saved his life. She is a hero."

What about Larry the cat?

Image copyright Downing Street Image caption Larry the cat is known as the chief mouser and lives at No 10, but is unlikely to see much of the dog

Mr Abraham said it was unlikely there would be much contact between the dog and the No 10 cat, Larry, as he would be living in the flat and having walks around St James Park.

But, he added: "He has been living in a foster home with a cat and is house-trained, and is doing the basic commands already."

The puppy was in foster care for five weeks having been abandoned by an unlicensed puppy farm in west Wales because it was regarded "unsellable" due to a misaligned (overshot) jaw.

Charity owner Eileen Jones, of Ynysybwl, Rhondda Cynon Taf, described Dilyn's journey from unwanted puppy to Downing Street as a "Cinderella story".

"It's a wonderful rags to riches story but, for such a small dog, he has a huge amount on his shoulders," she said.

"His adoption raises awareness of the campaign against puppy farming and also highlights the importance of adopting, rather than shopping for puppies.

"It's great that Carrie and Boris have picked such a normal, scruffy little terrier rather than some designer pooch.

Image copyright Parsons Media Image caption Carrie Symonds posted pictures with her new pet on Twitter

"He's had a great start, he was well-looked after and has taken his favourite toys and bed. He's a real little character and I'm sure he's going to settle in."

Lucy's Law is being rolled out in England next year and the Welsh Government has also confirmed it will adopt the law but no date has been set yet.

FOAW added: "We know only too well why Lucy's Law is such an important piece of legislation because we pick up the pieces of third-party puppy selling every day.

"The suffering of these dogs is unimaginable unless you see it first-hand as we have done for so many sad years."