The Ministry of Defence says that similar missile defence systems have been deployed at all recent Olympic Games.
They will be in place by mid-July, along with Royal Navy helicopter carrier HMS Ocean (which will be moored in the River Thames), Royal Air Force Typhoon jets (which will be temporarily stationed at RAF Northolt), and Puma helicopters (at a Territorial Army centre in Ilford).
More top news
Southern Railway has announced it will reinstate more than 100 daily train services which were cut to make its timetable more "resilient".
An 18-year-old boy is fighting for his life in hospital after being shot in the head.
Broadcaster Jeremy Vine has published shocking footage of of him “getting a kicking” from an angry driver during a heated confrontation.