Surface-to-air defence systems will be deployed at six sites in and around London during the 2012 Olympic Games, the Government confirmed today.
They are pressing ahead with the deployment in the face of a potential legal challenge from east London residents who do not want the systems pitched on the roof of their tower block home.
The ground-based air defence systems will be in place by mid-July.
Defence Secretary Philip Hammond said: "Ground-based air defence systems will form just one part of a comprehensive, multi-layered air security plan which, I believe, will provide both reassurance and a powerful deterrent."
The Government, based on military advice, has now given the go-ahead for the ground-based air defence systems, which will include Rapier and High Velocity Missile systems.
The main aim is to protect the Olympic Park in Stratford, east London, and its surrounding area from would-be attacks from the air.
High Velocity Missiles will be based at the Lexington Building in Tower Hamlets and the Fred Wigg Tower in Waltham Forest, both in east London.
Rapiers will be set on Blackheath Common and at Oxleas Meadow, Shooters Hill, both in south east London.
To the east there will be a Rapier based at Barn Hill and one at Netherhouse Farm in Epping Forest, and another at the William Girling Reservoir on the Lea Valley Reservoir Chain in Enfield, north London.
The mix of capabilities, including radar and detection equipment as well as weapons, should be both a powerful deterrent and protection device, according to the Government.
Similar systems have been deployed at all recent Olympic Games.
Home Secretary Theresa May said: "Our focus is to deliver an Olympic and Paralympic Games that London, the UK and the world can enjoy. The Games should be a peaceful celebration of sporting achievement and cultural celebration.
"But this is the biggest sporting event in the world, and with that comes the huge responsibility to deliver it safely and securely. We are working to a robust safety and security strategy and we will leave nothing to chance.
"The police and emergency services have substantial experience of major events and will bring this to bear with support from the military.
"Our approach is intelligence-led and risk-based, and flexible to respond to changes between now and the Games."
Solicitors instructed by the residents' association at the Fred Wigg Tower said their challenge is set to reach the High Court on July 9.
Residents have bitterly complained of a lack of effective consultation but officials are confident they can defend their position.
Other defence equipment including Royal Navy helicopter carrier HMS Ocean which will be moored in the River Thames will also be in place by mid-July.
There will also be Royal Air Force Typhoon jets, which will be temporarily stationed at RAF Northolt, and Puma helicopters at a Territorial Army centre in Ilford will also be in position by then.
The London 2012 Olympics run from July 27 to August 12.