Four people died in today's Westminster terror attack, including the police officer who was stabbed and his attacker, Scotland Yard's top anti-terror officer Mark Rowley has confirmed.
North East boxer: I saw policeman stabbed in Westminster attack
The knifeman brought terror to the heart of Westminster, mowing down pedestrians with his car on London's Westminster Bridge, including schoolchildren.
He then rushed at the gates in front of the Houses of Parliament, stabbing a policeman, before he was shot by armed officers.
Eyewitnesses described scenes of terror when gunfire rang out as the attacker approached a second officer within yards of the Houses of Parliament.
Paramedics fought to save his life and that of his police victim on the floor of the cobbled courtyard in front of Parliament, with Foreign Office minister Tobias Ellwood among those who rushed to help.
The police officer was wheeled away on a stretcher with his face covered, and sources later confirmed he had died.
* One pedestrian hit by the attacker's car before he reached Parliament was confirmed dead by a doctor at St Thomas' Hospital.
* Others on the bridge suffered 'catastrophic injuries'.
* At least one of the people being treated in the palace courtyard was wheeled away on a stretcher with their face covered.
* Another woman who apparently jumped into the Thames as the attacker drove across the bridge was rescued and given urgent medical treatment on a nearby pier.
* London Ambulance Service said paramedics had treated at least 10 patients on Westminster Bridge.
* A party of French schoolchildren were among those targeted on the bridge.
* Downing Street said Prime Minister Theresa May, who was ushered away from Parliament after the attack, was chairing a meeting of the Government's emergency Cobra committee.
* Commander BJ Harrington of the Metropolitan Police said there were "a number of casualties" in the attack "including police officers". He urged Londoners to be vigilant, said more officers would be on patrol and that anti-terrorism measures were being reviewed.
The knifeman drove a grey Hyundai i40 across Westminster Bridge before crashing it into railings then running through the gates of the Palace of Westminster.
His attack left a trail of destruction as paramedics tended to victims on the bridge and at the gate.
Mrs May was seen being ushered into a silver Jaguar in the grounds of the palace as what sounded like gunfire rang out at around 2.45pm.
Eyewitness Rick Longley described the attack.
"We were just walking up to the station and there was a loud bang and a guy, someone, crashed a car and took some pedestrians out.
"They were just laying there and then the whole crowd just surged around the corner by the gates just opposite Big Ben.
"A guy came past my right shoulder with a big knife and just started plunging it into the policeman.
"I have never seen anything like that. I just can't believe what I just saw."
Sunderland Central MP Julie Elliott said: "We are in the Chamber - we are in the safest place. It is scary.
"There is nobody who really know what is going on. We have to stay in here, we are on lockdown. We could not leave if we wanted to.
"Luckily, we were in the middle of voting, so everybody was in or around the chamber."
As the sitting in the House of Commons was suspended, Commons Leader David Lidington told MPs: "What I am able to say to the House is there has been a serious incident within the estate.
"It seems that a police officer has been stabbed, that the alleged assailant was shot by armed police.
"An air ambulance is currently attending the scene to remove the casualties.
"There are also reports of further violent incidents in the vicinity of the Palace of Westminster but I hope colleagues on all sides will appreciate that it'd be wrong of me to go into further details until we have confirmation from the police and from the House security authorities about what is going on."
Witnesses described seeing a middle-aged man carrying a knife and running.
Jayne Wilkinson said: "We were taking photos of Big Ben and we saw all the people running towards us, and then there was an Asian guy in about his 40s carrying a knife about seven or eight inches long.
"And then there were three shots fired, and then we crossed the road and looked over. The man was on the floor with blood.
"He had a lightweight jacket on, dark trousers and a shirt.
"He was running through those gates, towards Parliament, and the police were chasing him."
Her partner David Turner added: "There was a stampede of people running out.
"You saw the people and you thought 'what the hell is going on'."
After the incident, Radoslaw Sikorski posted a video to Twitter purporting to show people lying injured in the road on Westminster Bridge.
Mr Sikorski, a senior fellow at Harvard's Centre for European Studies, wrote: "A car on Westminster Bridge has just mowed down at least 5 people."
.Houghton and Sunderland South MP Bridget Phillipson said: "We were voting when a major incident developed. It's not claer what's happening.
"We are locked in the chamber."
Washington and Sunderland West MP Sharon Hodgson MP Tweeted: "we are all safe and on lockdown. Thankful for our amazing parliamentary security staff and Metropolitan police," while her Easington MP Grahame Morris said: "For those asking, am in the constituency this week. Hoping all my friends and colleagues in Westminster are safe."
Staff in the constituency office of Hartlepool MP Iain Wright say he is in Parliament, but is safe.
Stockton North Alex Cunningham Tweeted: "Thank you everyone for asking after me on this terrible day. We are in lock down and are safe in the Commons chamber."