Latest: Police name 52-year-old Westminster attacker

Latest: The man police believe to be behind the terrorist attack in Westminster has been formally identified as 52-year-old Khalid Masood.

Update 4.35pm: The Westminster terror attacker has been named as Khalid Masood.

Scotland Yard said the 52-year-old was not the subject of any current investigations and there was "no prior intelligence about his intent to mount a terrorist attack".