In more recent times, there's a Chief Mouser to the Cabinet Office: https://en.wikipedia.org/wiki/Chief_Mouser_to_the_Cabinet_Of...
> The Downing Street website describes Larry's duties as "greeting guests to the house, inspecting security defences and testing antique furniture for napping quality". It says he is "contemplating a solution to the mouse occupancy of the house" and has told Downing Street that such a solution is still in the "tactical planning stage"