There have long been questions on the role of the British territory in the rendition of US terror suspects. But not even the Senate’s damning report on CIA black sites has answered them

It was July 2005 and Jack Straw was in combative mood. During a parliamentary debate, the then foreign secretary insisted that there was no need for a judicial inquiry into the UK’s role in extraordinary rendition – “unless we all start to believe in conspiracy theories and that the officials are lying, that I am lying, that behind this there is some kind of secret state which is in league with some dark forces in the United States”.

But the publication last week of a long-awaited US Senate intelligence report has raised fresh questions about what the UK knew about the CIA’s torture programme – and in particular the role played by an obscure overseas British territory.

Al-Jazeera reported earlier in the year that the committee had seen evidence that Diego Garcia, an atoll in the Indian Ocean, had been used for extraordinary rendition “with the full cooperation” of the UK. But when the heavily redacted report was published, it made no mention of Diego Garcia, raising questions about whether references to it had been removed at the request of the UK.

The questions were not without foundation. Earlier this year the Observer revealed that senior British diplomats had met Senate committee members more than 20 times since they started their investigation, prompting claims that they had lobbied for certain exclusions. Last week Downing Street insisted that any requests for material to be redacted were made solely on the grounds of national security.

Whatever the reason, diplomats on both sides of the Atlantic will have felt relief that the atoll did not feature in the senate report: the UK is soon to start talks with the US about the future of Diego Garcia, and both sides have a vested interest in securing a new agreement. Under the current arrangement, in return for the US being allowed to operate a major naval base on the atoll, the UK receives a discount on the research and development costs of the US-led nuclear weapons programme, Trident.

As Foreign Office minister James Duddridge told parliament in September: “The US base on Diego Garcia represents a vital part of the Anglo-American defence relationship, remains a significant strategic asset for the UK and has previously been used for UK military operations.”

Facebook Twitter Pinterest Jack Straw: ‘Simply no truth in the claims that the UK has been involved in rendition.’ Photograph: Dan Kitwood/Getty Images

But extending the 50-year agreement, which expires at the end of next year, would be difficult to sell to the British public if it was confirmed that the atoll had played a key role in the CIA’s torture programme. A Foreign Office spokesman said no decision would be taken until after the election.

Whether the truth about Diego Garcia will emerge before then appears unlikely, something that will be a concern for lawyers, human rights groups and MPs who have expressed frustration at the way their attempts to establish exactly what happened has been received by Foreign Office officials, members of the intelligence services and ministers.

Andrew Tyrie, chairman of the all-party parliamentary group on extraordinary rendition, and the former attorney general Dominic Grieve now believe a judicial inquiry is the only way to establish the UK’s true role. Diego Garcia would be a cornerstone of any investigation, as there is credible evidence that it was used in the rendition programme. Six years ago, the then foreign secretary David Miliband was forced to confirm that two rendition flights had refuelled at Diego Garcia in 2002.

Manfred Nowak, the United Nations’ former special rapporteur on torture, told the Observer in 2008 that he had interviewed sources who told him detainees were held on Diego Garcia between 2002 and 2003. A former US general, Barry McCaffrey, has said that Diego Garcia held detainees, although he later withdrew the claims. A CIA flight plan shows that in 2004, the agency planned to render Abdelhakim Belhadj, an opponent of Libya’s Muammar Gaddafi, and his pregnant wife, via Diego Garcia.

Testimony filed in the high court by a Royal Marine, Michael Blyth, who represented the Foreign Office in Diego Garcia, said the US had initially talked about using the atoll to hold up to 500 suspects. The request, made in the weeks shortly after 9/11, was written off “within about 30 minutes”, according to Blyth, because there was “no current physical or logistical capacity”.

A response recently released by the Foreign Office under the Freedom of Information Act confirms that Britain had its own detention facilities on the atoll. It states “space was designated for use as a detention facility in 2001, [but] construction of the facility was not completed and it did not come into use until 2007. BIOT [British Indian Overseas Territory] Administration officials on Diego Garcia have confirmed that the prisoners held there before 2007 were detained in the police cells located adjacent to the current detention facility.”

The extent to which the 40 or so British personnel on the atoll would have been aware it was being used for rendition is unclear. Some 1,000 US military personnel and almost 2,500 civilians are based on Diego Garcia, many working for the private security giant G4S which has the multimillion-dollar contract to operate the base.

In his testimony Blyth explained: “After 9/11, the runway at DG was heavily used. Scores of planes took off daily, mostly supporting operations in Afghanistan.

“British customs officers did check customs and passenger manifests for planes that were offloading in DG. However, normal protocols were not to inspect military aircraft in transit. If a prisoner was held at the back of a plane in transit, and did not get off, then their presence on DG is unlikely to have been noticed by British officials.”

Attempts to track the planes, flown by private contractors known to have been involved in the rendition programme, have been thwarted by what former foreign secretary Margaret Beckett has acknowledged was poor record-keeping. In a further embarrassing twist, it emerged that the records of some flights had been subjected to water damage.

Now hopes that last week’s Senate report would finally shed light on Diego Garcia’s role in the CIA torture programme have been dashed. Now the next UK government could agree its future without the world learning the truth about its past.

“Until we have got to the bottom of the UK’s part in the CIA rendition programme, it is hard to see how renewing the US lease on the island can be justified,” said Clare Algar, executive director of Reprieve, which represents a number of people who were rendered by the CIA. “This should be postponed until the British public has been given the answers it deserves.”

DIEGO GARCIA LINK

1966 The UK signs a deal allowing the US to use Diego Garcia as a base.

11 September 2001 Attacks on the eastern seaboard of the US signal the beginning of the “war on terror”. Shortly afterwards the CIA initiates its extraordinary rendition programme.

2003 Stories start surfacing in the media suggesting Diego Garcia has been used for rendition. The claims are denied by a series of government ministers.

13 December 2005 Foreign Secretary Jack Straw, dismisses calls for an inquiry into the UK’s role, saying: “There simply is no truth in the claims that the United Kingdom has been involved in rendition, full stop.”

18 July 2007 Foreign Office minister Lord Malloch-Brown tells parliament: “The US authorities have repeatedly given us assurances that no terrorist suspects have been, or are being, held on Diego Garcia, or at any time have passed in transit through Diego Garcia or its territorial waters or airspace.”

21 February 2008 Foreign Secretary David Miliband tells parliament that “contrary to earlier explicit assurances that Diego Garcia had not been used for rendition flights, recent US investigations have now revealed two occasions, both in 2002, when this had in fact occurred.”

April 2014 Al-Jazeera reports that officials familiar with the entire 6,600 page unredacted US Senate intelligence report conclude that the CIA detained high-valuesuspects on Diego Garcia with the UK’s “full cooperation”.