The prime minister said that his son and daughter had been lobbying for a German shepherd, but he managed to talk them into a Siberian kitten instead.

Politics Live: Deputy PM won't rule out ditching council tax discount for singles

"There's been a long summer of negotiations, back and forth, different options," he revealed in a BBC 5 Live interview with Matt Chorley.

"But now we've gone for - and this is agreed after long negotiations - I said we'd get in the room and sort it out - we are now getting a kitten instead of a dog.

"This is a Siberian kitten, which is being picked up today by my daughter, and so that's where it ended up."

However, the new pet will face one big problem - alongside sharing the spotlight with Downing Street's resident mouser, Larry the cat.

Sir Keir revealed the only door out of Number 10 is bombproof, and "therefore getting a cat flap is proving a little difficult".

This has already caused issues for the Starmers' family cat, a rescue named JoJo, who the prime minister previously said is "revered" by his teenagers.

"Our daughter persuaded us that the problem isn't any bigger for two cats than one. And therefore, we're now getting this kitten," he said.

The new kitten will join a long line of pets with access to the heart of Downing Street

Larry, Downing Street's famous feline, has become something of a celebrity figure over the last decade, often appearing in the street during important political moments while serving as chief mouser to the last six prime ministers.

Read More:
Starmer attacked for removal of Thatcher portrait
Is it possible to 'ringfence' family time as PM?

Alongside Larry - who is looked after by Downing Street staff - Rishi Sunak and his family were joined by Nova, a Labrador retriever, during the former prime minister's tenure.

Nova took over as Britain's top dog from Dilyn, a Jack Russell adopted by Boris and Carrie Johnson.

Sarah Elliott, central veterinary officer for Cats Protection, said the charity was "pleased to hear there will be another feline voice in Downing Street".

She added: "As the junior member of the growing cat coalition at Downing Street, the prime minister and his family will need to take plenty of time to slowly introduce the new addition to JoJo and Larry.

"Young kittens can be exhausting for older statesmen like Larry, so he'll also need a safe, quiet area to retreat to when the energy of a younger member of the team gets a bit too much."