A Wimbledon resident has described the terrible moment he witnessed a terror attack on the streets of Westminster.

Four people were killed and at least 20 others injured in the attack, after a man drove into pedestrians on Westminster Bridge before stabbing and killing policeman PC Keith Palmer outside Parliament.

From yesterday: Four people, including police officer, killed as pedestrians are mowed down in Westminster terror attack

From today: Tributes paid to hero police officer Keith Palmer killed in Westminster terror attack

The man, who has not yet been named, was shot dead by police during the attack on the afternoon of Wednesday, March 22.

Andrew Boyce, of Morden Road, south Wimbledon, said he heard the sound of gun shots while working in an office in Parliament Square.

Mr Boyce said: “It all happened so quickly.

"We went to the window and could see the cop on the ground, and they were performing CPR on him.

“In the other direction, we could see the crashed car in the barriers of Parliament. People were crawling under the car to see if anyone was trapped underneath, but we didn’t know the driver had done what he did on the bridge.

“We could see the police cordoning off the area. We saw the air ambulance land on the ground.

“We all just had to get back to work, but we were watching the news and trying to find out what was happening. We tried to just get on with things. We were trying not to panic.

“It was very surreal. For the first hour or two there was a feeling of confusion. It wasn’t quite clear what had happened. It was only later on in the afternoon and we found out the policeman had been stabbed.”

Mr Boyce and his colleagues were initially warned not to leave the building, but were given the all-clear by 4.30pm.

Mr Boyce said: “When we were allowed to leave, we could see tourists were carrying on with what they were doing, seemingly oblivious to what had happened. They were smiling and laughing and didn’t seem impacted, and in a way that’s probably quite hopeful.

“Over the last few years there have been more barriers, more armed officers, and I think we expected something like this would happen. But you can only prepare so much, you can only feel prepared so much for something like this."

He added: “It’s not made me more nervous to work here. Most people who work around Westminster are slightly more vigilant about this sort of thing anyway, so that will continue or maybe become more prominent. But I don’t think we will let it change anything else.”

Were you in Westminster yesterday? Contact the newsdesk on 020 8722 6337 or pippa.allen@newsquest.co.uk