What happened?

Attacker Khalid Masood, 52, killed four pedestrians and injured about 50 others as he mowed down members of the public with a car on Westminster Bridge at about 2:40pm on Wednesday.

He then crashed his hired Hyundai SUV into the railings in front of Parliament Yard before bursting through the gate to the Palace of Westminster with two large knives where he fatally stabbed unarmed Pc Keith Palmer, 48.

He was shot dead moments later by a close protection officer attached to Defence Secretary Sir Michael Fallon.

The attack sent Westminster into lockdown and MPs were forced to stay put in the House of Commons for more than four hours while the area was made safe.

Prime Minister Theresa May had just voted and was standing in members' lobby with other Tory MPs. She was seen being quickly ushered into a silver Jaguar in the grounds of the Palace of Westminster and whisked away to the safety of Downing Street.