Journalist Quentin Letts has given talkRADIO an eyewitness account of yesterday's attack, saying the assailant approached Parliament "in a sort of casual run" before two officers converged on him.
Around 2:30pm on Wednesday aftermoon, a man in a speeding vehicle mowed down several pedestrians on Westminster Bridge, before crashing into the gates at the Houses of Parliament and running into New Palace Yard.
He fatally stabbed a police officer, PC Keith Palmer, before being shot dead by police. Four people - including the attacker - died in the incident, and there are thought to be up to 40 injured.
Letts, a correspondent for the Daily Mail, works in an office in the Palace of Westminster, which overlooks New Palace Yard. He told Paul Ross what he saw when the man ran into the yard.
He said: "Two policemen in yellow jackets threw themselves onto him, and one of them died as a result. I saw the attacker go at them, with his arm moving in and out.
"Then I saw him running towards Parliament, looping in a sort of casual run. Two plain-clothes people [police officers] challenged him, he didn't stop, and so they shot him.
"What I saw yesterday was men and women doing what they’re paid to do, and doing it very well.
"This is our citadel, the heart of our democracy. I feel outraged a man has attacked our parliament and run over innocents in the street."