Image copyright AFP

The UN Convention against torture defines it as "deliberately inflicting severe physical or mental pain or suffering" for reasons such as obtaining information or punishment. But countries rarely accept that their own interrogation techniques, however harsh, amount to torture, writes Dr Frank Foley.

As they came to terms with the shock of 9/11, people at the highest levels of the US government wanted to mete out a ferocious response to al-Qaeda suspects.

"When we're through with them, they will have flies walking across their eyeballs," said Cofer Black, a leading CIA counterterrorism official.

He may have meant the suspects encountered on the battlefield rather than those in the interrogation room - but the phrase illustrates the determination to hit back. The US was at war.

The use of torture, though, was clearly prohibited by both international and domestic US law.

"Everyone was focused on trying to avoid torture, staying within the line, while doing everything possible to save American lives," Bush administration lawyer Timothy Flanigan has been quoted as saying.

The English secret service practised torture with discretion Ernesto Geisel, Former Brazilian president

What happened was that "the line" bent.

To rise to the level of torture, one legal memo argued, the interrogator would need to intend to cause suffering "equivalent in intensity to the pain accompanying serious physical injury, such as organ failure, impairment of bodily function, or even death".

This gave US officials licence to use a whole range of brutal methods, including waterboarding, "rectal feeding", and sleep deprivation for up to a week, usually standing or in painful stress positions.

When details of the CIA's "enhanced interrogation" programme began to emerge, from 2004 onwards, allegations of US torture circulated around the world, together with the already notorious images of Guantanamo Bay detainees bound and gagged in orange jumpsuits.

Image copyright AFP

The Americans were about to learn a lesson that the British had already learned decades earlier in the Northern Ireland conflict.

In the second half of the 20th Century, Britain's security forces developed what they called the "five techniques": hooding, white noise, a diet of bread and water, sleep deprivation, and being forced to stand in a stress position against a wall for long periods.

We now know that British agents trained officers of Brazil's military dictatorship in these techniques.

We tortured some folks US President Barack Obama, (August 2014)

The report of Brazil's Truth Commission into the excesses of the dictatorship - published on the same day as the US Senate Intelligence committee's report into the CIA's "detention and interrogation program" - quoted former Brazilian President Ernesto Geisel saying that officers learned from the British secret service. They "practised torture with discretion", he said, while Brazil's "inexperienced staff did it in a more extrovert and open manner".

The British government, like the US until the Obama presidency, has always denied that its techniques, which were still being used in the Northern Ireland conflict in 1971, constituted torture. The European Court of Human Rights also ruled in 1978 that they constituted "inhuman and degrading treatment" rather than torture, though it will soon be asked to reconsider.

Regardless of the label, the brutality of these techniques was widely condemned when details were revealed. The UK's international reputation was tarnished and it lost a good deal of moral authority in its fight against terrorism.

So when the 9/11 and 7/7 attacks took place, British officials did not react by using such techniques on the terrorist suspects they were interrogating. In a communication issued in January 2002, MI5 and MI6 explicitly warned their agents in the field against engaging in torture themselves, not least because they could be prosecuted for doing so, given the prohibition of torture contained in the UK's Human Rights Act, stemming from the European Convention of Human Rights.

Image copyright AFP Image caption Binyam Mohamed was interviewed by an MI5 officer after his interrogation in Pakistan

Yet some in the British intelligence services still appeared to believe that torture could be an effective means of gaining information. UK officials co-operated with foreign governments' coercive interrogations of British citizens and others.

In one notorious case, Binyam Mohamed, a UK resident, was abused or tortured by intelligence officials in both Pakistan and Morocco during 2002. After his interrogation by Pakistani agents, Mohamed was interviewed by an MI5 officer. MI5 also allegedly supplied information to the CIA, which was then handed to Moroccan agents and used as the basis for their interrogations of Mohamed under conditions of torture.

In 2009, President Obama put an end to the CIA's use of waterboarding and other extreme interrogation techniques, citing the damage they had caused to the US's reputation and moral authority in the fight against al-Qaeda.

The vast majority of terrorist suspects maintain their right to silence Peter Clarke, Former Metropolitan Police counterterrorism chief

He also declared that the only interrogation techniques now allowed were those contained in the US Army Field Manual (AFM).

This represented a major change, though critics point out that the AFM still permits techniques such as prolonged isolation, sensory deprivation and sleep deprivation.

Obama also set up the High-Value Detainee Interrogation Group, which emphasises conventional techniques, such as building rapport with the suspect as a means of extracting information. And for a serving political leader he has been unusually frank, saying in August: "We tortured some folks." This week he repeated that some of the CIA interrogation methods "constituted torture in my mind".

FBI officials have long been critical of the CIA's brutal approach to interrogation. They argue passionately that their non-coercive interrogation techniques are effective in extracting information from detainees.

The British police take a similar approach, but they have been more willing to admit that some hardened criminals and terrorist suspects may simply refuse to talk.

As Peter Clarke, a former head of counterterrorism at the London Metropolitan Police, put it in 2008: "The vast majority of terrorist suspects maintain their right to silence… the walls of Paddington Green police station rarely reverberate with outpourings of guilt and contrition."

So despite the obsessive efforts of the Bush administration to force detainees to reveal information, the US and the UK may now be operating in a context where a significant number of terrorist suspects do not talk and are allowed to remain silent.

Image copyright Getty Images

Yet if there is an impasse in the interrogation room, Western societies have not suffered any major increase in terrorist attacks as a result of this.

Rather, security agencies in the US, UK and elsewhere have made an intensive effort to get their terrorism intelligence from other sources, such as informants, agents and signals intelligence. Many terrorist plots have been detected and foiled and there has been no major attack by a jihadist group on a Western city since the London bombings of 2005.

Following publication of the Senate report, there have been calls for the prosecution of Bush administration officials involved in the CIA's interrogation programme. This would send the strongest possible warning signal to any future US government considering re-authorising such techniques.

Security officials believed that their brutal treatment of detainees would remain largely secret

But even short of that, the revelations and public debate on the CIA's interrogation programme may yet prove to be a powerful deterrent.

A fundamental underpinning of the post-9/11 interrogations was a belief among security officials that their brutal treatment of detainees would remain largely secret.

US officials involved in the interrogation of Abu Zubaydah sought assurances that he would continue to be "in isolation and incommunicado for the remainder of his life", thus ensuring that his story would never be revealed to the public.

British intelligence officials also appear to have believed that they could maintain their covert co-operation with foreign governments' coercive interrogations without this involvement becoming public knowledge - and therefore with no effect on the UK's moral authority or international reputation.

They were wrong.

Allegations of torture did surface, investigative journalists followed them up, human rights advocacy groups campaigned on the issue and governments were taken to court. In a post-Snowden world, intelligence agencies also have less of a guarantee that their programmes will remain completely secret.

However, if these forms of public scrutiny ever weaken, officials may yet return to carrying out brutal acts in the name of national security.

Frank Foley is a Lecturer in the War Studies Department at King's College London, and author of Countering Terrorism in Britain and France.

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