A police officer and two other people have died close to the Houses of Parliament as a result of what police are treating as a terrorist attack. Their suspected assailant was shot dead by police after the fatal stabbing of their fellow officer, who was unarmed. The other victims died after a car was driven into them on Westminster Bridge.
At least 20 others were injured by the car, some very badly. An injured woman was rescued from the Thames and is reportedly in critical condition. Three French school children and two Romanians were also among those struck. [See postscript 23 March below].
The incident took place at about 14:40. Witness reports suggest the attacker drove along the pavement on the bridge before leaving the car and entering the grounds of parliament. Foreign office minister Tobias Ellwood MP tried unsuccessfully to resuscitate the police officer who was stabbed there.
In a video statement, London Mayor Sadiq Khan has vowed that “Londoners will never be cowed by a terrorist attack”. He said his thoughts were with the family of the Met officer who died and he thanked the police and emergency services for their “tremendous bravery” in dealing with the events.
Assuring Londoners and visitors that “our city remains one of the safest in the world,” the Mayor said: “We stand together in the face of those who seek to harm us and destroy our way of life. We always have and we always will.”
Parliament will sit as normal tomorrow. The Met has asked members of the public to call 0800 789 321 if they see anything concerning or suspicious and to please give them any film or photos they took of the attack.
Last updated at 22:05.
Postscript 23 March 2017: The total death toll rose overnight from four to five, including the attacker. The police officer killed has been named as PC Keith Palmer, aged 48.
Londoners have been responding on Twitter. Here’s Brent Councillor Sam Stopp.
Tom Boadle of Sky News posted this from Victoria Embankment. 
The Met has urged anyone in the area who saw anything suspicious to contact them.
BBC London’s transport correspondent Tom Edwards was close by. Everything was pretty much at a standstill at first.
From traveller and writer Jo Davey.
Here’s the 16:45 update from the London Ambulance service.
MP for Twickenham Tania Mathias reassures friends and families that she and her staff are safe.
