British military chiefs said they hoped the deployment of surface-to-air missiles in a London park would "allay people's fears" as the armed forces geared up for the 2012 Olympic Games.
The Rapier and smaller high-velocity missiles were deployed as part of Exercise Olympic Guardian, a nine-day training operation to test the response to a possible attack during the Games.
The missiles were shown off in Blackheath, southeast London, on high ground overlooking Greenwich Park, where the equestrian events will be held, and the steel-and-glass towers of the Canary Wharf financial services district.
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," he said.
Air Vice Marshal Stuart Atha said there was no specific threat to the Olympics, but that system aimed to "detect at the earliest possible stage a range of potential airborne threats".
Blackheath Common - where the annual London Marathon begins - is one of four planned sites around London for Rapier deployment. As part of the training exercise, Typhoon fighter jets are stationed near the capital, along with military helicopters and the amphibious assault ship HMS Ocean.