Police officers react as they attempt to cross a road through the path of runners during the the Vitality London 10km run in central London, on May 29, 2017.
Operation Temperer, which involved the deployment of armed troops on patrol alongside police, will be wound down on Monday night, at the end of the holiday weekend. Prime Minister Theresa May lowered the terror threat level, which had been hiked following the May 22 attack at Manchester Arena.  / AFP PHOTO / Daniel Leal-Olivas        (Photo credit should read DANIEL LEAL-OLIVAS/AFP/Getty Images)