Witness fights back tears as he describes moment policeman was attacked

The attack took place in the middle of the day, at a time when Westminster was heaving with witnesses.

Rick Longley saw a man lunge and stab a policeman after a car ploughed into pedestrians.

Fighting back tears, he told the Press Association: “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.”

Others who saw what happened took to social media to post pictures, videos and accounts.

Radoslaw Sikorski posted a video to Twitter purporting to show people lying injured in the road on Westminster Bridge.

The senior fellow at Harvard Centre for European Studies said he saw at least five people lying on the ground after being “mown down” by a car.

“I heard what I thought was just a collision and then I looked through the window of the taxi and saw someone down, obviously in great distress,” he told the BBC.

“Then I saw a second person down, and I started filming, then I saw three more people down, one of them bleeding profusely.”

Witness Quentin Letts said he saw a man in black attack a police officer outside Parliament before being shot two or three times as he tried to storm into the House of Commons.

“I saw a thick-set man in black clothes come through the gates into New Palace Yard, just below Big Ben,” he told the BBC.

“He had something in his hand, it looked like a stick of some sort, and he was challenged by a couple of policemen in yellow jackets.

“And one of the yellow-jacketed policemen fell down and we could see the man in black moving his arm in a way that suggested he was stabbing or striking the yellow-jacketed policeman.”

The other officer ran to get help and the man in black ran about 15 yards towards the entrance, he said.

He added: “As this attacker was running towards the entrance two plain-clothed guys with guns shouted at him what sounded like a warning, he ignored it and they shot two or three times and he fell.”

A London bus driver described the moment he saw the 4x4 plough into pedestrians after speeding across Westminster Bridge.

Michael Adamou, 25, was driving the 453 bus when he said he saw a grey Hyundai 4x4 speeding in the direction of Parliament.

He said: “As I turned left out of Whitehall, so turning left to go over the bridge, I saw a car knock two people over.

“Initially I thought he’s lost control of the car but then I see quite a few people rushing into Parliament and police trying to stop everyone.

“After a few seconds I just heard gunshots. Everybody on my bus was panicking.”

He said the driver “literally started from the hospital heading towards Parliament and just mowed down whoever was in his way.

Bradford Buck, from Connecticut in the US, saw the incident unfolding and took cover with his wife.

He said: “Police cars just kept coming one after another after another, I’ve never seen such a quick response. Then a little bit later the helicopter came.

“Police officers were running with machine guns, and there was a man down right next to the car.”