In the 1970's, during its own "war on terror" in Northern Ireland, the UK military went down a dark path, using the "five techniques" - wall-standing, hooding, noise, sleep deprivation and starvation - in an effort to break and intimidate the Irish. Ireland took them to the European Court of Human Rights, and in 1978 the court ruled that those techniques constituted inhuman and degrading treatment in violation of the ECHR. In response, the UK government gave a solemn and "unqualified" undertaking that the five techniques "will not in any circumstances be reintroduced as an aid to interrogation".
It seems they lied. A UK intelligence unit has been running amok in Iraq, using exactly those techniques in an effort to break and intimidate the Iraqis:
Fresh evidence has emerged that British military intelligence ran a secret operation in Iraq which authorised degrading and unlawful treatment of prisoners. Documents reveal that prisoners were kept hooded for long periods in intense heat and deprived of sleep by defence intelligence officers. They also reveal that officers running the operation claimed to be answerable only "directly to London".This is not a few "bad apples", using methods they have seen on American TV. They claimed to have been trained in these techniques back in the UK - meaning a conscious decision was made to ignore the court ruling and the UK government's undertaking. It also means a conscious decision was made to ignore the UN Convention Against Torture, which classifies both hooding and sleep deprivation as torture.
Torture is a crime under both UK and international law. As a party to the Convention Against Torture, the UK government has a positive obligation to prosecute it. The question now is whether they will uphold that obligation, or treat it with the same contempt they have showed for their previous undertakings.