Traffic has been stopped and offices cleared in Borough High Steet, in the shadow of the Shard, near London Bridge station, as police descend on the vehicle.
Pictures from the scene show police have surrounded a black car parked in a bus lane, and a cordon has been put in place to hold pedestrians back. A photograph posted on Twitter indicates that the vehicle is an Opel model – which are available in continental Europe but known as Vauxhall in Britain – and appears to have a foreign number plate.
A Metropolitan Police spokesman confirmed officers were sent to Borough High Street at 7.52am to reports of a “suspicious vehicle”.
He added road closures are in places and the investigation was in its “early stages”.