Here are the latest updates:
- The attacker has been identified as Khalid Masood, a 53-year-old born in Kent
- Isis claims responsibility for atrocity
- Theresa May reveals suspect was British citizen
- Police say attack is linked to Islamic extremism
- At least eight people have been arrested after overnight raids in London and Birmingham
- Four people were killed in the attack and 40 injured, some seriously
- Terrorist among those dead after being shot by police
- Killed police officer identified as PC Keith Palmer
- Aysha Frade, another victim, was on the school run
- Kurt Cochran, an American tourist visiting London, was also killed
- Seven others remain critically injured
- Police have asked for the identity of the terrorist not to be revealed by the media
- Parliament to meet again as normal this morning
- In pictures: Pictures show chaos and confusion after attack
- Miracle escape: woman has been pulled alive from River Thames
- Timeline of terror: How events unfolded
- What we know about the attacker
- Video captures moment police shoot dead terrorist
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Armed police have launched a late-night raid on an address in Birmingham.
West Midlands Police referred inquiries about the operation on Hagley Road to the Metropolitan Police, who refused to say whether it was connected with Wednesday’s attack in Westminster.
But a witness who works nearby told the Press Association: “The man from London lived here.”
Officers stormed a second-floor flat above a row of shops on Hagley Road at around 11pm, the witness said.
He added: “They came and arrested three men.”
One of the flat’s windows was covered in cardboard, with non-uniformed officers spotted taking pieces of equipment into the property.
As he was describing the events, the witness was interrupted by a police officer, who had been guarding the scene.
He had his details taken and was convinced to go to a police station with another officer.