The Jack Russell-cross started his life in a Welsh puppy farm and will now live with the PM and his partner Carrie Symonds.
Dilyn, a 15-week-old Jack Russell-cross, was picked out by the prime minister from an adoption centre in Wales.
The dog started his life in a Welsh puppy farm and had been “destined for an uncertain existence at the hands of a puppy dealer because he was born with a crooked jaw”, Friends of Animals Wales (FOAW) said.
Dilyn has now had his little jaw fixed and is now expected to have a full happy life with Boris & Carrie who absolutely adore him.
Larry the Cat has not yet met the new resident at Downing Street but he is believed to be not happy about the decision but has promises to be on his best behaviour.