Alberto Gonzales, the former US attorney-general, reportedly approved the use of waterboarding and other controversial interrogation techniques in a memo in 2005 even though the justice department had publicly declared that torture was “abhorrent”.

The justice department denounced the use of torture in December 2004, in a move seen as a retreat from the so-called 2002 “torture memo”, which appeared to condone the use of torture on terrorism suspects.