A number of major roads in London are on lockdown after a car crashed into barriers outside the Houses of Parliament this morning.
Police arrested a man following the incident close to a car park at the House of Lords entrance.
Smoke could be seen coming from the bonnet of the vehicle and a number of pedestrians have been injured.
Following the crash, several roads have been closed while police investigate.
Parliament Square has been closed off and more than 10 police vehicles and at least three ambulances remain outside.
Armed officers have also shut off Millbank from the scene to Lambeth Bridge until noon as a result.
Other road closures include Westminster Bridge, Great George Street, parts of Victoria Street and Broad Sanctuary.
All are currently on lockdown until midday at the least.
A spokesman for TfL said: ‘Parliament Square is closed clockwise between Bridge Street and Broad Sanctuary due to an emergency services incident.
‘There are other various local closures. Use alternative routes. Expect delays.
‘Westminster Bridge is closed northbound.’
Westminster station has shut for both entry and exit, however is currently open for interchange.
A witness said that several cyclists were hit during the collision.
Scotland Yard has not yet confirmed whether the incident is terror-related, but counter terror officers are at the scene.
Police said in a statement: ‘At 0737hrs today, a car was in collision with barriers outside the Houses of Parliament.
‘The male driver of the car was detained by officers at the scene.
‘A number of pedestrians have been injured. Officers remain at the scene. We will issue further info when we have it.’