Larry has been stalking the corridors of power since 2011, when he was brought into the prime minister’s office to handle pest control affairs.
Larry had a lingering look up at May as she entered Number 10 on Tuesday for Cameron’s final cabinet meeting as prime minister.
And he did not seem perturbed by her trademark leopard-print kitten-heel shoes.
There had been fears that Larry would be following the Camerons out of the door when May takes over as prime minister on Wednesday.
But while government members nervously await their fate, officials insisted the nine-year-old brown and white tabby was staying on and would survive May’s forthcoming reshuffle.
“It’s a civil servant’s cat and does not belong to the Camerons,” a Cabinet Office spokeswoman said. “He will be staying.”
Larry, a rescue cat, was brought into Downing Street after a rat was spotted in two television news bulletins scurrying around outside the famous black door of the prime minister’s residence.
However, Larry’s work rate has been called into question.
Downing Street says the nation sends him daily gifts and treats but he spends much of his time “testing antique furniture for napping quality”.
There have been resident mice-fighting cats in Downing Street since the 1920s. Some have even been given the title of “chief mouser to the Cabinet Office” and put on the state payroll.
The legendary Humphrey, a stray who took up residence under prime minister Margaret Thatcher and outstayed John Major, was sent into retirement in 1997 by Tony Blair, amid persistent speculation that his wife Cherie forced him out.
Humphrey was on the payroll, receiving £100 ($130, 120 euros) a year from the Cabinet Office budget.
Cameron’s six-year government has tried to reduce Britain’s budget deficit and Larry’s upkeep is now paid for by Downing Street staff.
Larry has been seen in several stand-offs with Palmerston, the Foreign Office cat brought in in April.
He is also thought to have difficult relations with Freya, finance minister George Osborne’s family cat.
Osborne’s official residence is next door at 11 Downing Street and Freya would be on the move if May shifts Osborne from his Treasury post.