Britain's most senior police officer witnessed the terror attack at Westminster, he has confirmed.

Acting commissioner of the Met Police Craig Mackey is being treated as a significant witness as he was on the scene.

He was not one of those injured.

Seven arrested and six addresses raided in connection with Westminster attack

Speaking outside Scotland Yard just yards from the scene of the attack, Mr Mackey said: "I personally was a witness to part of yesterday's events, including part of the tragic attack on PC [Keith] Palmer.

"As with all police officers, I therefore had a duty to secure my evidence and produce statements yesterday evening, which I did before resuming my role leading our response to this incident."