There seems to be a keenness to introduce this new technique at the expense of manned helicopters which IMHO does not sit well with such a critical event as the Olympics. New technology + aviation = high risk.
I've just done a job with 5 helicopters airborne at a time, 5x microwave links ect, covering a sports event for TV. I don't see why technically, the met can't bring in more aircraft for three weeks, a more reliable option than "going for gold" with UAVs.
If there is a prospect of numerous police drones and TV sports micro drones flying around the Olympics, who will be able to identify and act if the bad guys decide to launch one of their own?
Mickjoebill