Being strapped onto the stretcher by compassionate ambulance staff, the Asian man in his 40s receives treatment after driving a 4x4 across Westminster Bridge, injuring 40 people.
Two objects that appear to be knives can be seen on the concrete next to the attacker, who then drove into the gates of the Palace of Westminster and stabbed a police officer to death.
An Asian man in his 40s, believed to be the attacker, is put on a stretcher and wheeled into an ambulance inside the grounds of Parliament with two knives (circled) left on the cobbles.
Being strapped onto the stretcher by compassionate ambulance staff, the Asian man in his 40s receives treatment after driving a 4x4 across Westminster Bridge, injuring 40 people
At least five people died this afternoon - including him - after the knifeman mowed down pedestrians then stabbed a policeman before he was shot by armed officers
The suspect's face can be clearly seen as he lies on his back on the stretcher, with his shoes on the floor and his shirt open, revealing what appear to bandages on his stomach.
The man drove a year-old Hyundai Tucson - worth up to £32,000 and registered in the affluent Essex city of Chelmsford - down Westminster Bridge at 'high speed' before attacking the officer.
The car - which is thought to have been a rental vehicle - can accelerate from 0 to 60mph in as little as 9.5 seconds and was registered between September 2016 and February 2017.
The man is believed to have been the only attacker although police locked down the area on a 'precautionary basis' tonight in case someone else was still at large.
Metropolitan Police assistant commissioner Mark Rowley told reporters outside New Scotland Yard tonight: 'We're satisfied at this stage that it looks like there was only one attacker, but it would be foolish to be overconfident so early on.
'So, for precautionary basis, we're locking down the area and doing all the necessary searches so we can be completely confident that everyone is safe.'
At least three civilians were killed on the bridge, as well as the police officer who was stabbed and his attacker.
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 victim on the floor of the courtyard in front of Parliament. Two large knives could be seen at the scene.
Witnesses described seeing a heavy-set man carrying a knife. Jayne Wilkinson said: 'We were taking photos of Big Ben and we saw all the people running towards us.
The driver crashed into Parliament's railings this afternoon and then rushed the gates and stabbed a police officer in the head and the neck before he was shot by another officer
'And then there was an Asian guy in about his 40s carrying a knife about seven or eight inches long.
What do we know about the 4x4 in the attack?
The vehicle driven into Parliament's gates this afternoon was a Hyundai Tucson worth between £19,000 and £32,700.
The black diesel car was registered between September 2016 and February 2017 in Chelmsford, Essex.
The car can accelerate from 0 to 60mph in as little as 9.5 seconds and the model has been made by the South Korean manufacturer since 2004.
All cars registered in Essex are registered to Chelmsford, which is where the Driver and Vehicle Licensing Agency's regional office is located.
Hyundai cars are registered in Essex when they are imported into the Port of Tilbury - and it is thought the car could have been a rental vehicle.
'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.'
One pedestrian hit by the attacker's car before he reached Parliament was confirmed dead by a doctor, while others suffered 'catastrophic injuries'.
At least one of those 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 pier.
London Ambulance Service said paramedics had treated at least ten patients on the bridge. French school children were among those targeted.
Prime Minister Theresa May, who was ushered away from Parliament after the attack, will chair a meeting of the Government's Cobra committee.
MPs were locked in the House of Commons for more than two hours and business was suspended after the attack, which happened at about 2.40pm.
At least four people died this afternoon after the knifeman mowed down pedestrians, crashed into Parliament's gates (above) then stabbed a policeman before he was shot by armed officers
Earlier, there were claims that a 'bald white man' and a 'black man with goatee beard' had been seen, following initial earlier reports that only the Asian man was involved.
But Britain's most senior anti-terror officer Mr Rowley later dismissed these claims, saying it was believed that only one suspect was involved in the attack.
Essex Police Acting Assistant Chief Constable Andy Prophet said: 'In Essex tonight, and until further notice, there will be increased visible police patrol including additional armed officers and other specialist resources.
'I urge the public to be alert but not alarmed. Police forces and our partners are doing everything we can to help protect the security of our citizens, public institutions, critical national infrastructure, and businesses and places.'