The existence of a secret, CIA-run prison on the island of Diego Garcia in the Indian Ocean has long been a leaky secret in the “War on Terror,” and today’s revelations in TIME — based on disclosures by a “senior American official” (now retired), who was “a frequent participant in White House Situation Room meetings” after the 9/11 attacks, and who reported that “a CIA counter-terrorism official twice said that a high-value prisoner or prisoners were being interrogated on the island” — will come as no surprise to those who have been studying the story closely.

The news will, however, be an embarrassment to the US government, which has persistently denied claims that it operated a secret “War on Terror” prison on Diego Garcia, and will be a source of even more consternation to the British government, which is more closely bound than its law-shredding Transatlantic neighbor to international laws and treaties preventing any kind of involvement whatsoever in kidnapping, “extraordinary rendition” and the practice of torture.

This is not the first time that TIME has exposed the existence of a secret prison on Diego Garcia. In 2003, the magazine broke the story that Hambali, one of 14 “high-value detainees” transferred to Guantánamo in September 2006, was being held there, and in the years since confirmation has also come from other sources. Twice, in 2004 and 2006, Barry McCaffrey, a retired four-star US general, who is now professor of international security studies at the West Point military academy, revealed the prison’s existence. In May 2004, he blithely declared on MSNBC’s Deborah Norville Tonight, “We’re probably holding around 3,000 people, you know, Bagram air field, Diego Garcia, Guantánamo, 16 camps throughout Iraq,” and in December 2006 he spoke out again, saying, in an NPR interview with Robert Siegel, “They’re behind bars … we’ve got them on Diego Garcia, in Bagram air field, in Guantánamo.”

The prison’s existence was also confirmed by Dick Marty, a Swiss senator who produced a detailed report on “extraordinary rendition” for the Council of Europe in June 2007 (PDF) and by Manfred Novak, the UN’s Special Rapporteur on Torture, in March this year. Having spoken to senior CIA officers during his research, Marty told the European Parliament, “We have received concurring confirmations that United States agencies have used Diego Garcia, which is the international legal responsibility of the UK, in the ‘processing’ of high-value detainees,” and Manfred Novak explained to the Observer that “he had received credible evidence from well-placed sources familiar with the situation on the island that detainees were held on Diego Garcia between 2002 and 2003.” The penultimate piece of the jigsaw puzzle came in May, when El Pais broke the story that “ghost prisoner” Mustafa Setmariam Nasar, whose current whereabouts are unknown, was imprisoned on the island in 2005, shortly after his capture in Pakistan — although the English-speaking press failed to notice.

Despite these previous disclosures, today’s article, by Adam Zagorin, is particularly striking because of the high-level nature of the source, and his admission that “the CIA officer surprised attendees by volunteering the information, apparently to demonstrate that the agency was doing its best to obtain valuable intelligence.” In addition, the source noted that “the US may also have kept prisoners on ships within Diego Garcia’s territorial waters, a contention the US has long denied.”

Zagorin also spoke to Richard Clarke (at the time the National Security Council’s Special Advisor to President Bush regarding counter-terrorism), who explained, “In my presence, in the White House, the possibility of using Diego Garcia for detaining high value targets was discussed.” Although Clarke “did not witness a final resolution of the issue,” he added, “Given everything that we know about the administration’s approach to the law on these matters, I find the report that the US did use the island for detention or interrogation entirely credible,” and he also pointed out that using the island for interrogations or detentions without British permission “is a violation of UK law, as well as of the bi-lateral agreement governing the island.”

Zagorin’s source did not name the prisoners, but it seems clear that the period he was referring to (“2002 and possibly 2003”) was when three particular “high-value detainees” — Abu Zubaydah, Khalid Sheikh Mohammed and Ramzi bin al-Shibh — are reported to have been held on the island, and it seems entirely plausible, therefore, that after these three were transferred to another secret CIA facility in Poland, the prison was used not only to hold Hambali, but also to hold the two other “high-value detainees” captured with him — Mohammed bin Lep (aka Lillie) and Mohd Farik bin Amin (aka Zubair). The addition of Mustafa Setmariam Nasar, who, it seems, may have been held into 2006, not only confirms that a secret prison existed, but that it was possibly in use for four years straight.

These damaging revelations seal Diego Garcia’s reputation as a quagmire of injustice. A British sovereign territory — albeit one that was leased to the United States nearly 40 years ago, when the islanders were shamefully discarded by the British government and exiled to face destitution and death by misery in Mauritius — Diego Garcia has long been a source of shame to opponents of modern colonial activity. Until now, however, the only admission that any activities connected with the “War on Terror” had taken place on the island came in February, when, after years of denials on the part of the British government, David Miliband, the Foreign Secretary, finally conceded that requests for information from his US counterparts had revealed that, in 2002, two rendition flights had refuelled on the island. “In both cases,” Miliband stated with confidence, “a US plane with a single detainee on board refuelled at the US facility in Diego Garcia. The detainees did not leave the plane, and the US Government has assured us that no US detainees have ever been held on Diego Garcia.”

The British government had been provoked to action by critics within the UK, in particular the All-Party Parliamentary Group on Extraordinary Rendition, led by the Tory MP Andrew Tyrie, and the legal action charity Reprieve, which represents 30 prisoners in Guantánamo, but the story appeared to grind to a halt when Michael Hayden, the CIA’s director, stepped forward to deny that Diego Garcia had ever been used as a “War on Terror” prison.

“That is false,” Gen. Hayden said when asked if a secret prison had existed on Diego Garcia, adding, as the New York Times put it, that “neither of the two detainees carried aboard the rendition flights that refuelled at Diego Garcia ‘was ever part of the CIA’s high-value terrorist interrogation program.’” He also explained that one of the detainees “was ultimately transferred to Guantánamo,” while the other “was returned to his home country,” which was identified by State Department officials as Morocco. “These were rendition operations,” he added, “nothing more.”

Four weeks ago, however, the story resurfaced once more, as David Miliband reported the results of his latest request for information from his US counterparts. This concerned a list of rendition flights, which, in the opinion of Reprieve and the All-Party Parliamentary Group, may also have passed through British territory, but the Foreign Secretary was confident that there was no further evidence to be mined, stating, “The United States Government confirmed that, with the exception of two cases related to Diego Garcia in 2002, there have been no other instances in which US intelligence flights landed in the United Kingdom, our Overseas Territories, or the Crown Dependencies, with a detainee on board since 11 September 2001.”

Yet again, the assurances of his US colleagues did nothing to assuage the critics. Reprieve noted that the British government “intentionally failed to ask the right questions of the US, and accepted implausible US assurances at face value,” and added, presciently, “This remains a transatlantic cover-up of epic proportions. While the British government seems content to accept whatever nonsense it is fed by its US allies, the sordid truth about Diego Garcia’s central role in the unjust rendition and detention of prisoners in the so-called ‘War on Terror’ cannot be hidden forever.”

Just three days after David Miliband’s last attempt to draw a line under the story, the British Foreign Affairs Select Committee published its latest report on the British Overseas Territories (PDF), and was scathing about Diego Garcia, declaring that “it is deplorable that previous US assurances about rendition flights have turned out to be false. The failure of the United States Administration to tell the truth resulted in the UK Government inadvertently misleading our Select Committee and the House of Commons. We intend to examine further the extent of UK supervision of US activities on Diego Garcia, including all flights and ships serviced from Diego Garcia.”

Today’s revelations, of course, leave the US administration looking like bald-faced liars and the British government looking like myopic dupes. Whether Michael Hayden was also duped is not known, but his strenuous denial, just five months ago, that a secret prison existed, which was manned by his own employees, will do nothing for the credibility of the US administration, which likes to pretend that it does not torture and has nothing to conceal, but is persistently discovered not only being economical with the truth, but also behaving exactly as though it has guilty secrets to hide.

Whether this scandal will awaken much indignation in the American public remains to be seen, but it is hugely damaging to the British government, which is legally responsible for the activities that take place on its territory, however much it likes to hide behind “assurances” from its leaseholders that they have done nothing wrong.

It scarcely seems possible, but Diego Garcia’s dark history has suddenly grown even darker.

The prisoners held on Diego Garcia

Abu Zubaydah (Zayn al-Abidin Muhammad Husayn). Saudi, b. 1971. Seized in Faisalabad, Pakistan in a joint operation by Pakistani forces and the FBI on 28 March 2002, he is regarded by the administration as a senior al-Qaeda operative and training camp facilitator, although this has been disputed by former FBI interrogator Dan Coleman, who has described him as a minor logistician with a split personality.

In February 2008, Gen. Michael Hayden, the director of the CIA, admitted that Abu Zubaydah was one of three prisoners who had been subjected to waterboarding (an ancient torture technique that involves controlled drowning) in CIA custody. Held initially in Thailand, and later in Poland, he is one of 14 “high-value detainees” transferred to Guantánamo in September 2006. At his tribunal in 2007, he denied being a member of al-Qaeda, and made a point of mentioning that he had been tortured. He has not yet been put forward for trial by Military Commission.

Khalid Sheikh Mohammed. Kuwaiti/Pakistani, b. 1964 or 1965. The supposed mastermind of the 9/11 attacks, Mohammed (commonly known as KSM) was seized in Rawalpindi, Pakistan on March 1, 2003. Like Abu Zubaydah, he was subjected to waterboarding, and is also presumed to have been held initially in Thailand, and later in Poland. Transferred to Guantánamo in September 2006, he confessed to being “responsible for the 9/11 operation, from A to Z” at his tribunal in 2007, but also made a point of mentioning that he had been tortured. He was put forward for trial by Military Commission in February, and will face the death penalty if convicted.

Rumors that KSM was held on Diego Garcia have surfaced sporadically over the years, one example being an article in the Toronto Star on July 2, 2005 (mirrored here), in which Lynda Hurst spoke to John Pike, a US defense analyst. Pike, who told Hurst that he believed that KSM had been held on Diego Garcia, explained, “Diego Garcia is an obvious place for a secret facility. They want somewhere that’s difficult to escape from, difficult to attack, not visible to prying eyes and where a lot of other activity is going on. Diego Garcia is ideal.”

Ramzi bin al-Shibh. Yemeni, b. 1972. A friend of the Hamburg cell that led the 9/11 attacks, bin al-Shibh was seized in a raid in Karachi, Pakistan on September 11, 2002. He was reportedly intended as the 20th hijacker, but was unable to obtain a visa to enter the United States, and subsequently worked closely with KSM in planning the attacks. Transferred to Guantanamo in September 2006, he is also presumed to have been held initially in Thailand, and later in Poland, but his presence on Diego Garcia has long been suspected, because analyses of flight records have revealed that a plane flew from Pakistan to Diego Garcia immediately after his capture. He refused to take part in his tribunal in 2007, but was put forward for trial by Military Commission in February, and will face the death penalty if convicted.

Hambali (Riduan Isamuddin). Indonesian, b. 1966. Seized in Ayutthaya, Thailand in a joint operation by Thai forces and the CIA on 11 August 2003, he is regarded as the main link between al-Qaeda and its Indonesian counterpart, Jemaah Islamiyah (JI). He is alleged to have been one of the planners of the Bali bombings in October 2002, which killed over 200 people, and was transferred to Guantánamo in September 2006. At his tribunal in 2007, he said that he resigned from JI in 2000, and was not involved with al-Qaeda or with any bombings or plots. He has not yet been put forward for trial by Military Commission.

Lillie (Mohammed Nazir bin Lep) and Zubair (Mohd Farik bin Amin). Malaysians, seized with Hambali, little is known of these two men, beyond claims by the administration that they worked closely with Hambali, although they were both discussed in another TIME article, in October 2003, which examined Hambali’s interrogation logs. They were transferred to Guantánamo in September 2006, but have not yet been put forward for trial by Military Commission.

Mustafa Setmariam Nasar (Abu Musab al-Suri). Syrian/Spanish, b. 1958. Seized in Quetta, Pakistan in October 2005 and handed over to US forces a month later, he is not accused of being involved in direct attacks on US forces, but is wanted in Spain as a witness in connection with the 2004 Madrid train bombings. Regarded as one of the most significant proponents of universal jihad, his writings include a 1600-page book, The Global Islamic Resistance Call, which was published on the internet in 2004. A critic of al-Qaeda, he reportedly fell out with Osama bin Laden in 1998, and has stated that the 9/11 attacks were catastrophic for the jihadi cause. Unlike the six prisoners mentioned above, he was not transferred to Guantánamo in September 2006, and it is not known, therefore, whether he is being held in a secret CIA prison or if he has been rendered to a third country.

Andy Worthington is the author of The Guantánamo Files: The Stories of the 774 Detainees in America’s Illegal Prison, which includes extensive chapters on rendition and secret prisons. The book is published by Pluto Press, distributed by Macmillan in the US, and available from Amazon — click on the following for the US and the UK. To receive new articles in your inbox, please subscribe to my RSS feed, and see here for my definitive Guantánamo prisoner list, published in March 2009.

As published on Antiwar.com, Indymedia, CounterPunch and ZNet. An edited version was published on the Huffington Post.

For a sequence of articles dealing with the use of torture by the CIA, on “high-value detainees,” and in the secret prisons, see: Guantánamo’s tangled web: Khalid Sheikh Mohammed, Majid Khan, dubious US convictions, and a dying man (July 2007), Jane Mayer on the CIA’s “black sites,” condemnation by the Red Cross, and Guantánamo’s “high-value” detainees (including Khalid Sheikh Mohammed) (August 2007), Waterboarding: two questions for Michael Hayden about three “high-value” detainees now in Guantánamo (February 2008), Six in Guantánamo Charged with 9/11 Murders: Why Now? And What About the Torture? (February 2008), The Insignificance and Insanity of Abu Zubaydah: Ex-Guantánamo Prisoner Confirms FBI’s Doubts (April 2008), Guantánamo Trials: Another Torture Victim Charged (Abdul Rahim al-Nashiri, July 2008), Will the Bush administration be held accountable for war crimes? (December 2008), The Ten Lies of Dick Cheney (Part One) and The Ten Lies of Dick Cheney (Part Two) (December 2008), Prosecuting the Bush Administration’s Torturers (March 2009), Abu Zubaydah: The Futility Of Torture and A Trail of Broken Lives (March 2009), Ten Terrible Truths About The CIA Torture Memos (Part One), Ten Terrible Truths About The CIA Torture Memos (Part Two), 9/11 Commission Director Philip Zelikow Condemns Bush Torture Program, Who Authorized The Torture of Abu Zubaydah?, CIA Torture Began In Afghanistan 8 Months before DoJ Approval, Even In Cheney’s Bleak World, The Al-Qaeda-Iraq Torture Story Is A New Low (all April 2009), Ibn al-Shaykh al-Libi Has Died In A Libyan Prison, Dick Cheney And The Death Of Ibn al-Shaykh al-Libi, The “Suicide” Of Ibn al-Shaykh al-Libi: Why The Media Silence?, Two Experts Cast Doubt On Ibn al-Shaykh al-Libi’s “Suicide”, Lawrence Wilkerson Nails Cheney On Use Of Torture To Invade Iraq, In the Guardian: Death in Libya, betrayal by the West (in the Guardian here) (all May 2009), Lawrence Wilkerson Nails Cheney’s Iraq Lies Again (And Rumsfeld And The CIA), and WORLD EXCLUSIVE: New Revelations About The Torture Of Ibn al-Shaykh al-Libi (June 2009). Also see the extensive archive of articles about the Military Commissions.

For other stories discussing the use of torture in secret prisons, see: An unreported story from Guantánamo: the tale of Sanad al-Kazimi (August 2007), Rendered to Egypt for torture, Mohammed Saad Iqbal Madni is released from Guantánamo (September 2008), A History of Music Torture in the “War on Terror” (December 2008), Seven Years of Torture: Binyam Mohamed Tells His Story (March 2009), and also see the extensive Binyam Mohamed archive. And for other stories discussing torture at Guantánamo and/or in “conventional” US prisons in Afghanistan, see: The testimony of Guantánamo detainee Omar Deghayes: includes allegations of previously unreported murders in the US prison at Bagram airbase (August 2007), Guantánamo Transcripts: “Ghost” Prisoners Speak After Five And A Half Years, And “9/11 hijacker” Recants His Tortured Confession (September 2007), The Trials of Omar Khadr, Guantánamo’s “child soldier” (November 2007), Former US interrogator Damien Corsetti recalls the torture of prisoners in Bagram and Abu Ghraib (December 2007), Guantánamo’s shambolic trials (February 2008), Torture allegations dog Guantánamo trials (March 2008), Sami al-Haj: the banned torture pictures of a journalist in Guantánamo (April 2008), Former Guantánamo Prosecutor Condemns “Chaotic” Trials in Case of Teenage Torture Victim (Lt. Col. Darrel Vandeveld on Mohamed Jawad, January 2009), Judge Orders Release of Guantánamo’s Forgotten Child (Mohammed El-Gharani, January 2009), Bush Era Ends With Guantánamo Trial Chief’s Torture Confession (Susan Crawford on Mohammed al-Qahtani, January 2009), Forgotten in Guantánamo: British Resident Shaker Aamer (March 2009), and the extensive archive of articles about the Military Commissions.