Formerly classified documents show the U.K. tortured its own citizens amid increased security measures after Sept. 11. Some of the papers implicate former Prime Minister Tony Blair’s office, and new P.M. David Cameron announced an investigation into the events. One set of documents shows MI5 officers complicit in the mistreatment of a British resident they were questioning at an American airbase in Afghanistan. The MI6’s procedural manual, “Detainees and Detention Operations,” says that during an operation to detain a terror suspect, officers should consider whether "detention, rather than killing, is the objective of the operation." A 2002 document says transferring citizens from Afghanistan to Guantánamo is the "preferred option." Another said Downing Street kept a British citizen held in Zambia from getting support from the consulate, resulting in him being “rendered” to Guantánamo. The documents have been uncovered as part of a civil suit by six former Guantánamo inmates against the British government, which has delayed the release of many papers citing the massive volume of relevant papers.