The video will start in 8 Cancel

News, views and top stories in your inbox. Don't miss our must-read newsletter Sign up Thank you for subscribing We have more newsletters Show me See our privacy notice Invalid Email

Footage has captured the trail of carnage on Westminster Bridge in central London immediately after a car mounted the pavement and ploughed into pedestrians.

The video shows people strewn across the pavement, some covered in blood, with members of the public and medical workers administering first aid.

The footage comes after at least four people died when a 4x4 smashed into people indiscriminately on the bridge, before crashing into railings outside the House of Parliament.

A man then got into the compound and stabbed police officer before being shot himself. The policeman, PC Keith Palmer, and attacker are among the dead.

For live updates on the suspected terror attack, click here

(Image: Trinity Mirror PLC)

This footage shows numerous casualties, some dressed in business clothes, lying, apparently unconscious.

As many as 20 people are believed to have been injured in the attack.

Chilling footage captured by a witness shows bystanders fleeing for their lives as police shoot the knife-wielding assailant after he got into the Parliamentary compound.

Other footage shows terrified tourists and others running away from Westminster and shouting at others unaware of the danger to flee.

Moments later three gunshots are heard in quick succession.

That was the moment, according to eyewitnesses, that police shot an attacker who had stabbed an officer at a security checkpoint leading to Parliament.

(Image: Twitter) (Image: Twitter)

Video Loading Video Unavailable Click to play Tap to play The video will start in 8 Cancel Play now

As people fled the scene and gunshots are heard the person who filmed the video is heard asking: "What happened?"

A man off camera tells him: "They shot him. [He] was running with a knife.

"They shot him. The police was trying to get him, he came running down there."

(Image: Twitter) (Image: Twitter)

(Image: PA)

(Image: PA)

Footage then shows a black car leaving Westminster as people run across the street to get away.

As people gather and watch they begin to speculate that it was a terror attack.

One man says: "We think it was an attempt or an attack or something because they shot. Look, police are putting everything down."

(Image: PA)

Video Loading Video Unavailable Click to play Tap to play The video will start in 8 Cancel Play now

As additional police officers arrive at the scene, the man adds: "That's not normal."

The video was recorded across the street at Parliament Square, where an air ambulance landed a short time later to pick up an injured person.

Photos showed emergency personnel tending to the injured officer and assailant, and a knife on the floor.

Jason Groves, a political editor who witnessed the incident from his office window, said: "I heard a bang coming from Westminster Tube station, looked out the window, there's a commotion, armed cops were running, the crowd of people outside were running as if for their lives.

(Image: PA)

(Image: PA) (Image: PA)

Video Loading Video Unavailable Click to play Tap to play The video will start in 8 Cancel Play now

"A guy comes through the vehicle entrance wielding something, towards a copper, the copper tumbles.

"The man's running towards Westminster Hall, and then you've got a plainclothes copper comes running out.

"Not from the gate, but from the inside, shoots him once from maybe 10 or 15 yards away with a handgun, and then gets closer to him and shoots him again from over him and he doesn't get up."

Journalist Patrick Daly recorded video of the aftermath as security personnel helped the injured police officer and assailant behind the gates.

(Image: PA) (Image: PA) (Image: Getty Images)

He said he heard gunshots and saw a man falling to the floor.

Mr Daly was in an office overlooking New Palace Yard when the dramatic incident unfolded on Wednesday afternoon.

He said: "We have all been told to stay away from the windows because of the shooting.

"I can't work out where the gunshot came from. A guy has been killed in front of us, I am assuming he is dead.

"It looked like a policeman was being lunged at."