>> At least 4 people are dead and 20 injured after what police are calling a terrorist attack here in central London. With parts of the city still on lock down I'm Reuter's reporter Mia Womersley outside the houses of Parliament where scenes of chaos and confusion unfolded throughout the afternoon.
It all began when a car came careening down behind me, across the river Thames and crashed into several people. A Reuters photographer says he witnessed dozens of people lying on the floor, some heavily bleeding. There are also reports of a woman who was pulled, alive but seriously injured, out of the river Thames.
It then seems that the assailant managed to make his way into the Houses of Parliament. He had a knife, and MPs say they witnessed him stabbing a policeman. He was then shot, they report hearing three or four gunshots, and the assailant was killed. We know that a policeman has also died, and two others, those two other victims believed to have been on the bridge.
London's Ambulance Service said it treated at least ten people. And the Press Association is quoting a doctor from the hospital just across the river, that's St Thomas', saying that they treated some patients who were critically injured. Police have cordoned off much of this area and in fact, there are still plenty of tourists trapped inside the London Eye.
They will eventually be allowed down and they are being treated as witnesses and so they'll be questioned by the police. Britain is on its second highest alert level, that's one off severe, which suggests that a militant attack is highly likely. Now members of the public are being told to stay away from this area and also to remain especially vigilant and report any suspicious activity to the police.
All of this of course, happening exactly a year to the day of the attack in Belgium carried out by Islamic State in which 32 people died,