In summary:
- 40 people hurt - including some with “catastrophic” injuries
- Identity of lone terrorist yet to be confirmed by police
- Woman Pulled Alive From Thames After Falling During Attack
- MP Former Soldier Hailed As Hero For CPR On Fallen Officer
- Shocked Eyewitnesses Describe Horror Scene At Westminster
- Theresa May Bundled Out Of Voting Lobby By Plain Clothes Police
UPDATE: Police revise death toll down from five to four.
Terror struck at the heart of British democracy on Wednesday after four people were killed - including the attacker and a police officer - at the Houses of Parliament.
Three others, one believed to be a female pedestrian, were killed during a car rampage on Westminster Bridge which also left at least 40 people hurt - including some with “catastrophic” injuries.
Scotland Yard tonight confirmed the police officer killed was PC Keith Palmer, 48, who was unarmed. He was married with children.
Police were originally believed to be investigating whether a second attacker was involved, but have since said they are not looking for another suspect.
He continued: “It would be wrong of me here to go into further details until we have confirmation from police and from the house security authorities about what is going on.”
Jeremy Corbyn said afterwards that his “thoughts are with the victims of this horrific attack, their families and friends”.
He added: “The police and security staff have taken swift action to ensure the safety of the public, MPs and staff, and we are grateful to them.”
Mayor of London Sadiq Khan also released a statement, saying:
“There has been a serious incident near to Parliament Square this afternoon which is being treated as a terrorist attack until the police know otherwise.
“I have spoken to the Acting Commissioner. The Metropolitan Police Service is dealing with the incident and an urgent investigation is underway. My thoughts are with those affected and their families.
“I would like to express any thanks to the police and emergency services who work so hard to keep us safe and show tremendous bravery in exceptionally difficult circumstances.”
The incident happened on the one year anniversary of the Brussels bombings, which killed 32 people and wounded more than 300.
In Scotland, MSPs have delayed a vote on a possible second independence referendum in light of the attack in Westminster. The Scottish Parliament and Welsh Assembly were both suspended for the day.
A BBC journalist also tweeted:
Police have opened a dedicated phone line for victims injured in the attack and concerned friends and family on: 0800 056 0944 or 0207 158 0010