Former Metropolitan Police Commissioner Sir Bernard Hogan-Howe has praised the "excellent leadership" of the force's acting head Craig Mackey in the wake of the Westminster outrage.
Deputy Commissioner Mackey witnessed part of the attack but was driven away from the scene. This has prompted some former officers quoted in the Daily Mail to question why he did not stay to help.
On Friday, Acting Deputy Commissioner Mark Rowley, the officer leading the investigation into the attack, dismissed questions about Mr Mackey's involvement, saying: "It's frustrating that we get nonsense like this from armchair critics."
Speaking yesterday outside New Scotland Yard, metres 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 Palmer.
"As with all police officers, I therefore had a duty to secure my evidence, and produced my statements yesterday evening, before resuming my role leading our response."
In his message to staff, Sir Bernard said: "I just wanted to let the Met know that I am thinking of you all right now.
"I particularly want to send my condolences to the family of Pc Keith Palmer, horribly murdered bravely defending Parliament.
"I am also thinking of the officers who were injured, some I know very seriously. And of course the poor members of the public so tragically murdered or still suffering life-changing injuries.
"I know I am no longer commissioner but didn't want you to think I had forgotten you all.
"I still care a great deal for you and know the great challenges you face day and night and the magnificent way you have responded over the last 24 hours under the excellent leadership of Craig Mackey."