More from our Political Correspondent Simon Harris:
Johnson: The 20/20 vision is there as another bench-marking tool but it's not the only one. @itvlondon
Johnson and Hogan-Howe are asked why rape is not included in the list of seven targeted crimes. @itvlondon
More top news
George Michael died in December last year at the age of 53.
PC Keith Palmer, 48, stabbed by Khalid Masood while on duty in the grounds of the Palace of Westminster last Wednesday.
Those gathered on the bridge fell silent at 2.40pm - the time the first call was made to police exactly seven days ago.