Washington's protectionist rhetoric is no idle threat: America's behaviour towards Japan in the mid-1980s shows that tub-thumping in Congress can quickly lead on to real protectionist action.

ECONOMIST: China should loosen its currency peg��and quickly

But the broad scientific consensus is that serious climate change is a danger, and this newspaper believes that, as an insurance policy against a catastrophe that may never happen, the world needs to adjust its behaviour to try to avert that threat.

ECONOMIST: Getting warmer

They also deter improper behaviour by the police themselves, a greater threat to both the targets of searches and the public than media exposure.

ECONOMIST: Law and the media

We also understand the need for a strong response to the everyday threat to people's security that comes from crime and anti-social behaviour.

BBC: NEWS | UK | UK Politics | In full: Cameron speech

Mr Eldergill said many psychopaths go through life committing anti-social behaviour but no serious crimes and it was impossible to predict those who were a real threat to the public.

BBC: Stone case could prompt law change