Sir Keir Starmer planning new pet for No 10

Tom Baldwin, a friend of the Prime Minister and the author of Keir Starmer: The Biography let details of the moggy mulling slip during an appearance at the Aye Write book festival in Glasgow.

The Labour leader was reportedly keen to install a cat flap in the No11 flat to allow JoJo to roam freely. However, the extra thick bombproof doors are also seemingly cat flap proof.

Mr Baldwin told the audience in Glasgow’s Royal Concert Hall that it compared favourably to Boris Johnson’s redecorating the flat with £840 a roll wallpaper.

He said: “Rather than putting gold wallpaper up, he’s trying to get a cat flap installed. Downing Street won’t actually let him do it, because these doors are like that thick and ballistic tested.

Asked if it was for Jojo, Mr Baldwin said it was. “They’re thinking of getting kittens, I can reveal,” he added.

Sir Keir had previously said that the cat was “treated with more respect” by his family than he is.

Before the election, he told BBC Derby: “We’ve got a cat called JoJo, revered by the kids. JoJo was a cat we got from a rescue centre.

“JoJo is treated with far more respect in our household than I am. When I walk through the door I have to put the baggage of being Leader of the Labour Party down, I’m Dad and I’m fair game for the kids to ridicule me, laugh at me etc.

“But JoJo, on the other hand, if JoJo wants food, or a seat on the settee, or to sit on the kid’s bed he’s got pride of place.”

Meanwhile, details have emerged of the protocol for announcing the death of Larry.

The 17-year-old chief mouser has been in Downing Street since 2011 and has served six prime ministers.

According to the Times, senior officials have drawn up a plan, known as “Larry Bridges.”

Photos of Larry in Downing Street have been specially selected to be released when the time comes. 

A second government insider confirmed the “Larry Bridges” plan had been pulled together for “the announcement of his death to the world”.

They added: “We felt it had to be handled so sensitively.”