WANT a camera that can spot a footprint from orbit, see through the most cunning camouflage or freeze images of bombs at the instant they blow? With the latest generation of digital cameras you can now photograph the seemingly impossible.

You no longer have to be paranoid to suspect that the government can see what you are reading by peering over your shoulder from space. Military imaging technology has almost certainly reached the point where digital cameras in spy planes flying at 60,000 feet are powerful enough to read a car's licence plate, and satellites more than 200 kilometres up can spot objects the size of a mobile phone.

Cameras on civilian satellites are catching up fast. The commercial QuickBird satellite is able to pick out objects just 60 centimetres across, while the Hubble Space Telescope, if pointed at Earth, could almost make out the contents of your wallet.

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