Apparently the British Prime Minister just dropped round his neighbourhood used car lot and picked out a 2004 K12 Micra. (Related: A brief history of the Nissan Micra.)
He looked over a petrol-powered 1.2L triple with a DIY gearbox -- the only car on the lot he considered -- plunked down £1,495 (about $2845 Canadian) and drove it home.
Supposedly one of his criteria for a car was that it was made in the U.K. (which Micras used to be, but I think they've since moved production to India).
The Telegraph says he got it for his wife to use as a runabout. But speculation is it could also be a stunt for a future Top Gear episode.