The twenty-eight collaborating "nations"

..some of them no nation at all, or a nation deported:.

DIEGO GARCIA(UK): a British possession in the Indian Ocean the U.S. has transformed into a powerful military base to dominate the Middle East and Asia. Reportedly, the CIA has a facility there that was used in 2005-06 to hold Mustafa Setmariam Nasar, a Syrian-Spanish national. According to Reprieve, “the UK has a significant military and administrative presence on Diego Garcia, which has its own independent administration run by the East Africa Desk of the Foreign and Commonwealth Office in London.” Reprieve further stated, “In October, 2003, Time Magazine cited interrogation records from the US prisoner Hambali that had reportedly been taken on the island, while respected international investigators at the Council of Europe and the United Nations expressed similar suspicions. US officials went on to make seemingly careless public statements confirming the use of Diego Garcia for secret detentions.”

Further reading.