A campaign group has said the US president should order a criminal investigation into alleged torture sanctioned by the Bush administration.

Human Rights Watch (HRW) says there is "overwhelming evidence" of torture ordered by George W Bush.

The former president has defended some of the techniques, saying they prevented attacks and saved lives.

The Obama administration has launched inquiries into deaths in CIA custody and other "unauthorised actions".

But HRW argues these inquiries will not cover the activities which were specifically authorised as legal by officials within the Bush administration.

The former president, vice-president, defence secretary and head of the CIA should all be investigated, the group says....