A car has crashed into a security barrier outside the Houses of Parliament, prompting a huge police response.
Armed police were seen surrounding the vehicle, which is believed to have hit several cyclists, at shortly before 8am on Tuesday.
Scotland Yard said a man has been arrested.
Armed officers could be seen surrounding the car before leading a man away in handcuffs.
A series of ambulances arrived at the scene.
One witness at the scene said it appeared that at least one cyclist was in the road being treated by paramedics.
Parliament Square was evacuated as a large number of police cars descended on the heart of Westminster.
Streets around Parliament Square, Millbank and Victoria Tower Gardens were also cordoned off as dozens of armed police swooped on the scene. (Telegraph)
