"[3] In the summer of 2003, Grey began investigating reports of the CIA's secret system of extraordinary renditions (transfer of terror suspects to foreign jails, where many faced torture).

[5] He went on to contribute to several front-page news articles to The New York Times about rendition and security issues, as well as to Newsweek, CBS 60 Minutes, Le Monde Diplomatique, and BBC Radio 4's File on Four.

By tracing the landings and takeoffs of clumsily concealed CIA flights, his work not only demonstrates concerned investigative journalism in action, it lifts the lid on a global gulag of prisons and torture chambers, assembled by US officials in defiance of domestic and international human rights law.

In a broadcast on the BBC World Service on 30 December 2009, reviewing the last ten years of journalism, author and campaigner Heather Brooke described Grey's investigation of the CIA rendition flights as the "journalistic scoop of the decade.

A Channel 4 Dispatches film reported by Grey titled "Afghanistan: Mission Impossible"[12] was short-listed for a Royal Television Society Award for independent film-maker of 2009.