Like Larry the Downing Street cat and Palmerston of the Foreign Office, the black cat is a former stray adopted from Battersea Cats and Dogs Home.
Amid mounting speculation that Larry and Palmerston are engaged in a turf war, Gladstone’s official Instagram page describes him as an animal with “catitude”.
And the 18-month old domestic short hair wasted no time in getting involved in the apparent spat.
A caption to a photo of Gladstone in a cat carrier reads: “Me on my first day at my new home. The humans had to keep me in this cage in case I ran down the street and tormented some other mouser called ‘Larry’. Personally, I’ve never heard of him. #movingday.”
Named after former prime minister and chancellor William Ewart Gladstone, his profile also describes him as “the most popular colleague at Her Majesty’s Treasury”, where he catches mice and “receives cuddles”.
After a recent “fracas” with Palmerston, Larry had to be treated by a vet after developing a limp in his front right paw.
It was unclear whether Palmerston was responsible but the Foreign Office’s “diplomog” has been pictured in recent days being evicted from No 10 and squaring up to Larry.