Anti-war protesters have set up camp outside an arms fair, being held at London's ExCel centre.
The DSEI event is described as the world's largest fully integrated defence and security exhibition, with nearly 30,000 visitors and 1,500 exhibitors.
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.