Larry's tenure as the chief mouser to the Cabinet Office (his official title) under Theresa May — who is moving in along with her husband, Philip — was confirmed on Wednesday as Prime Minister David Cameron and his family prepared to move out of the official residence.
As the world's press gathered outside 10 Downing Street to await Cameron's departure and the arrival of May, the brown and white tabby rescue cat could be seen prowling around before lying down for a nap.
That's Larry looking up from his cat nap as May arrived at 10 Downing Street on Tuesday, a day before she stepped into her new role.
The PM sought to end speculation he didn't like Larry.
During Cameron's final question period as prime minister he devoted some time to ending speculation that "somehow I don't love Larry. I do, and I have photographic evidence to prove it."
He then produced a picture of the cat lying on his lap.
The photo was also posted on Twitter.
Proof... pic.twitter.com/UZVXn6WcUw— @David_Cameron
An account attributed to Larry also acknowledged the transition at 10 Downing Street, as did BBC journalist Jack Evans, who apparently got the scoop.
With Dave gone, guess who's in charge for the next hour or so: pic.twitter.com/SeJXJcxzMy— @Number10cat
Larry is a legend on Downing Street.
The prime minister said he was sad he can't take Larry with him, because Larry "belongs to the house and the staff love him very much — as do I," he said.
A government spokesperson later confirmed that Larry was staying put. "It's a civil servant's cat and does not belong to the Camerons. He is a Downing Street legend."
Larry has been in residence since 2011. Here he is playing with some bunting in the garden on June 1, 2012, during celebrations to mark the Queen's Diamond Jubilee.
Mousing is only one of Larry's 'official' duties.
The official site chronicling 10 Downing Street's history says Larry "spends his days greeting guests to the house, inspecting security defences and testing antique furniture for napping quality" as well as his day-to-day job of finding a "solution to the mouse occupancy of the house" which, as the site says, is still "in tactical planning stage."
Larry is often seen getting a pet by the police officer positioned outside the residence.
There is precedent for Larry staying behind.
In earlier years, Larry's role was filled by a cat named Humphrey, who the BBC reports wandered as a stray into the PM's residence while it was occupied by Margaret Thatcher, as well as Gordon Brown's black and white mouser named Sybil Fawlty.
Larry, who was brought from the Battersea Dogs and Cats Home in 2011, was said to have a "strong predatory drive," suggesting he was well suited to his task, although there is scant evidence of the mouser's efficacy.
A recent meowing match with Palmerston, the Foreign Office's cat, captured by the BBC's Laura Kuenssberg, proves he is not afraid to stand his ground. (Put the sound on for this.)
Here is the exclusive video...... pic.twitter.com/YusArW8kkH— @bbclaurak
Larry also once got into a fight with Freya, owned by chancellor of the exchequer George Osborne, outside 10 Downing Street, documented by the Daily Telegraph.