Typhoon fighter jets overhead, the Navy’s largest ship HMS Ocean moored at Greenwich and ground to air missiles on Blackheath. It can only be the London Olympics. I’m sure these things are designed to deter attackers and maybe reassure Londoners but the sight of rocket launchers twitching into action, searching for a potential foe is slightly unnerving. The good news is that if the Rapier missiles miss there intended target they are programmed to explode in the air. That's the plan, let the games begin.