London Olympics: MoD shows off Rapier missile system

A large-scale security exercise is under way to enable the military to prepare for the key role it will play during the London 2012 Olympic Games.

One option being considered is the deployment of surface-to-air missiles at key sites, a plan that has drawn criticism from some residents.

Col Jon Campbell, Commander, Joint Ground Based Air Defence, spoke to the BBC to explain how the Rapier missile system might be used to counter an aerial security threat.