One woman has been killed in this afternoon's violent attack at Westminster which is being treated by police as a terror incident.
A number of people were also hurt after a car drove along the pavement on Westminster Bridge, leaving one person dead and a number of people with "catastrophic injuries" according to a doctor at St Thomas' Hospital. London Ambulance Service said it had treated 10 people on the bridge.
Parliament and other buildings in the surround area are currently on lockdown and Westminster Tube station is closed.
The police have issued the following statement:
Police are asking people to avoid 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.
This is to allow the emergency services to deal with the ongoing incident.
Police were called at approximately 14:40 hours to reports of an incident in Westminster Bridge, SW1. It is being treated as a firearms 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.
Police are appealing for any members of the public who may have images or footage of the incident to send them to this address:
The police also asked that members of the public "use common sense and restraint in circulating pictures and videos of those that have been injured during the incident".
Please use common sense and restraint in circulating pictures and videos of those that have been injured during the incident in #Westminster— Metropolitan Police (@metpoliceuk) March 22, 2017
Meanwhile, London Ambulance Service deputy director of operations Pauline Cranmer said:
We were called at 2.40pm to Westminster Bridge to reports of an incident, with the first crew arriving within six minutes.
We have sent a number of resources to the scene including ambulance crews, London’s Air Ambulance and our Hazardous Area Response Team.
We are working closely with other members of the emergency services at the scene, with our priority being to ensure patients receive the medical help they need as quickly as possible.
We have declared a major incident and our priority is to assess patients and ensure that they are treated and taken to hospital as soon as possible.
As we are very busy dealing with this incident, we would ask the public to only call us in a genuine emergency.