Military chiefs said today that they hoped to “allay people's fears” as they unveiled surface-to-air missiles which could be deployed at six sites across London during the Olympics.
The Rapier and smaller High-Velocity Missiles would be used as "prudent measures" to safeguard the Games and would be protected by armed police, the joint air defence team said.
The weapons were showcased at Blackheath Army Cadet Centre, in south east London, as part of a massive 2012 security test on land, sea and in the air.
Colonel Jon Campbell, commander of the Joint Ground Based Air Defence, said: "We have done as much as we can to allay people's fears.
"The Rapier system has a world-class radar on it and is particularly good at picking up low and slow-moving objects in the sky.
"It means we're able to get the very best picture of what is happening in the skies of London."
Air Vice Marshal Stuart Atha added: "We want the focus to be on Usain Bolt this summer and not us.
"We're very proud to be part of this plan to deliver a safe and secure Olympics."
The Lexington Building in Tower Hamlets and the Fred Wigg Tower in Waltham Forest, both in east London, have been identified as potential sites for the High Velocity Missiles.
Rapier missiles would be positioned on Blackheath Common and in Oxleas Wood, both in south east London, and at William Girling Reservoir Chain in Enfield and Barn Hill at Netherhouse Farm in Epping Forest, both in north London, should the Air Security Plan be approved by the Government.
Col Campbell said the sites had been chosen to avoid having weapons inside the Olympic Park.
He said: "We're trying to de-militarise this and let the sport do the talking.
"The Lexington Building is the best available location away from the Olympic Park."
Armed police will guard the missiles at the six potential sites during the Olympics and Paralympics should the plans be approved, Col Campbell said.
He said the decision to fire the weapons would be a "political decision" but refused to confirm if Prime Minister David Cameron's approval would be needed.
Col Campbell said he was "not prepared" to discuss the possible collateral damage caused by firing the missiles, adding: "I have every confidence to do the job which is asked of us."
Under the Air Security Plan, a 30-mile zone above the Olympic Park would become a restricted flying zone during the Games.
Observers would be placed at 14 sites to spot potential air threats using binoculars with thermal imaging detecting systems.
Helicopters with Royal Air Force (RAF) regiment snipers could be deployed to intercept aircraft that entered the restricted airspace without permission, the RAF said.
Air Vice-Marshal Atha said: "There is no specific threat to the Olympics at the moment...but the shape and nature of that threat could be wide and varied."
The test missile event in Blackheath follows the arrival of typhoons at RAF Northholt on Wednesday for the start of a nine day security exercise.
It is the first time fighter aircraft have been stationed at the airbase since the First World War.