Britain's foreign secretary Philip Hammond was forced to issue a denial after his own Conservative party colleague claimed the "chief mouser" at the UK's Foreign Office could be a European Union (EU) spy.
Palmerston, a cat that was adopted by the Foreign and Commonwealth Office, had been recently announced as the "chief mouser" to help tackle the problem of mice in the building in central London.
However, as the debate around Britain's membership of the EU heats up in the lead up to the June 23 referendum, a member of the camp in favour of remaining in the economic bloc told the House of Commons yesterday that those in favour of Brexitmay fear Palmerston has not been fully vetted.
"There is a serious point here. Can I ask my right honourable friend whether Palmerston has been security cleared or not... can I ask him, has he been positively vetted by the security service and scanned for bugs by GCHQ? And can my right honourable Friend assure the House and the more paranoid element in the Brexiters - that he isn't a long term mole working for the EU Commission," Tory MP Keith Simpson asked Hammond.
The foreign secretary chose to the address the bizarre query, claiming Palmerston's attendance record had been impeccable.
He told MPs: "He is definitely not a mole. I can categorically assure my honourable friend that Palmerston has been regularly vetted." more