The white and tabby cat, who bears the official title Chief Mouser to the Cabinet Office, was seen padding around the famous high-gloss black door to Number 10 - the office he will now share with his sixth prime minister.
Larry the cat, Chief Mouser to the Cabinet Office, has been a long-time resident at 10 Downing St. (AP PHOTO)
Larry has been resident in the seat of British power since 2011 when then-prime minister David Cameron adopted him from the nearby Battersea Dogs and Cats Home.
An unorthodox barometer on the state of British politics, he then served under prime ministers Theresa May, Boris Johnson, Liz Truss and Rishi Sunak during a tumultuous period of Conservative-led governments.
On Friday, his latest housemate, Labour Party leader Keir Starmer, took up office having won a landslide electoral victory.
Larry the cat is accustomed to waiting by the door of Number 10 until a policeman lets him in. (AP PHOTO)
While Larry is going nowhere, he might soon have some company - Starmer already has a cat named JoJo expected to join him at the residence.
Unperturbed by that prospect, Larry soon decided to ditch the unseasonably wet and windy weather by letting himself into Number 10 in his customary manner - waiting by the door until a friendly policeman opened it for him.