PC Keith Palmer, the unarmed police officer killed in yesterday's terror attack at Westminster, was a former soldier who served in the Royal Artillery.
Mr Palmer, who was a member of the Parliamentary and Diplomatic Protection Squad died as he tried to stop the attacker entering Parliament.
James Cleverly MP, also a former solider, tweeted:
The suspect, who was armed with two knives, injured around 40 people as he mowed down pedestrians with a car on Westminster Bridge before crashing at the railings in front of Parliament.
Bursting through the gate to the Palace of Westminster, the attacked stabbed PC Palmer before being shot dead by armed officers.
Theresa May praised the bravery of police officers last night as it was announced Westminster would attempt to run as smoothly as normal.
In a statement from Downing Street, the Prime Minister said:
"Any attempt to defeat the values of freedom and democracy through violence and terror is doomed to failure."
Paramedics and former army captain Tobias Ellwood fought to save PC Palmer on the floor of the cobbled courtyard in front of Parliament.
Mr Ellwood, who served in the Royal Green Jackets and lost his brother in the Bali bombing, could be seen pumping the police officer's chest then standing above him, his hands and face smeared with blood.
Defence Secretary Michael Fallon has said the working assumption is that the Westminster attack is linked to Islamic terrorism.
Armed police have carried out a raid linked to the terror plot that brought bloodshed to the heart of London, as MPs spearhead a show of defiance by returning to Parliament.
Officers stormed a flat in Birmingham late last night.
Mark Rowley, The Metropolitan Police's Head of Counter Terrorism confirmed the raid's connection to the bloody assault on Westminster, and one witness told the Press Association:
"The man from London lived here."
The House of Commons and the House of Lords will sit at their normal times today, despite the parliamentary estate playing unwilling host to the attack.
Counter-terror detectives will continue searching for clues as to how an armed attacker brought destruction to London.