Palmerston was in the news on 3 May 2016, as it was reported that he had caught his first mouse.[3] On 11 July 2016, Palmerston was caught on camera in a stand-off between himself and Larry in and around Downing Street.[4][5] On 26 July 2016, Palmerston was caught sneaking into Number 10, when the black door was left open. He was later evicted by resident police.[6] On 1 August 2016, a journalist caught Palmerston and Larry having a serious cat-fight, which led to Palmerston having damage to his ear and Larry losing his collar.[7]
In October 2017, Palmerston "appointed" his first overseas envoys. Lawrence of Abdoun, a rescued black-and-white street tomcat, was given a role at the British Embassy in Amman, Jordan, and is named after British military officer T. E. Lawrence and the neighbourhood in Amman where the embassy is located.[8] Leyla Pixie, an orphaned kitten from Turkey, was adopted by the British Consulate General in Istanbul.[9]
On 7 August 2020, Palmerston "retired" as the FCO's Chief Mouser, moving to the countryside to "spend more time relaxing away from the limelight"; his "resignation" was announced on Twitter.[10][11]