siddesu writes "The BBC has a nice high-level overview of some technologies for surveillance developed in the US and the UK. 'The US and UK governments are developing increasingly sophisticated gadgets to keep individuals under their surveillance. When it comes to technology, the US is determined to stay ahead of the game ... But it [a through-the wall sensing device in development] will also show whether someone inside a house is looking to harm you, because if they are, their heart rate will be raised. And 10 years from now, the technology will be much smarter. We'll scan a person with one of these things and tell what they're actually thinking.'"