Several people were injured after they were hit by a car, while two others were shot outside Houses of Parliament.

Eyewitnesses have reported a man with a knife within the perimeter of the Palace, while two people were shot and an officer stabbed. The alleged assailant, who was dressed in black, has now been shot by police.

Officers are on the scene and the area on the south side of Westminster is secured. An air ambulance is removing the casualties. Twelve people might have been injured.

An eyewitness who has spoken to Sky said he saw a 4x4 vehicle crash into a number of people and the railings of Parliament, before the driver abandoned the scene.

Theresa May is safe and was taken away by eight armed undercover policemen into a car forty yards from the gates outside Parliament. MPs remain in the main chamber or in their offices and Westminster is in lockdown.

Police are treating the incident as a terrorist attack. They are asking people to stay away from the following areas: Parliament Square; Whitehall; Westminster Bridge; Lambeth Bridge; Victoria Street up to the junction with Broadway and the Victoria Embankment up to Embankment tube.

In their statement, the police said: “This is to allow the emergency services to deal with the ongoing incident. Officers - including firearms officers - remain on the scene and we are treating this as a terrorist incident until we know otherwise. We thank the public for their assistance.”