AP Photo

If you've ever watched TV shows such as Spooks or 24, you'll have seen the government agencies calling up real-time satellite imagery to track hostile forces. It might make for good TV, but it's pretty far-fetched. While some spy satellites are supposed to have the capability to read the largest headline print of a newspaper someone is holding, satellites aren't generally in geo-stationary orbits, so unless they've been pre-positioned, the chances of a satellite being in the right place at the right time are fairly small.