There are now five cats on Downing Street.

The Cabinet Office confirmed to The Telegraph that they have adopted a black-and-white cat called Evie and another called Ossie to deal with the mouse problem in the Government offices.

A spokesperson said: "The cats are named Evie after Dame Evelyn Sharp, the first female permanent secretary, and Ossie after Sir Edward Osmotherly, author of the Osmotherly Rules, the guide that civil servants have when giving evidence to parliamentary select committees."