The "war on terror" has made the world a more insecure place than at any time since the end of the Cold War, Amnesty International said yesterday.

Britain and the United States are singled out in its annual report for eroding human rights in their crackdown on terrorism.

In Britain there have been "serious human rights violations".

"Many of those detained under 'anti-terrorism' legislation or on the basis of extradition warrants were held in inhuman or degrading conditions in high-security prisons," it said.

A Home Office spokesman refuted the allegations, saying the new powers are a "necessary and proportionate response to the threat we face".