Police officers joined a large gathering on Westminster Bridge to honour the victims of the attack which rocked London a week ago.
The congregation held a silent vigil for 82 seconds - the exact length of Khalid Masood's rampage last Wednesday.
Masood killed three pedestrians and injured up to 40 others after driving through crowds on the bridge, before fatally stabbing PC Keith Palmer outside Parliament.
He was shot dead shortly after the attack on PC Palmer.
The three victims on the bridge have been named as 54-year-old American Kurt Cochran, 75-year-old Leslie Rhodes, and 44-year-old Aysha Frade.
The Metropolitan Police Federation, which organised the event, said its purpose was to show "we will not be divided" and connect all "nations, faiths, orientation and sexes".