At 2.35am next day, the jet, after refuelling at Dulles airport in Washington, landed in Cairo and the suspects were handed to Egyptian authorities. Then, they vanished.

The operation was part of the CIA’s highly secret and increasingly controversial practice of “extraordinary rendition”, where terrorist suspects, some snatched off streets in daylight, are sent abroad for interrogation, often to countries with a record of using torture.

In recent weeks several former detainees have come forward and a picture is emerging of a global network, sanctioned by President Bush, of private jets owned by bogus companies, CIA snatch squads armed with drugs and mace spray and nighttime flights to Saudi Arabia, Jordan, Morocco and Afghanistan.

The Stockholm operation came to light after Paul Forrell, a police inspector on duty at the airport, gave a detailed account to the Swedish media. When the Swedish ambassador tracked the two men down to a Cairo jail five weeks later, they claimed they had been tortured. Al-Zery was eventually released. Agiza was sentenced to 25 years for membership of a radical Egyptian organisation.

The US Congress has uncovered many other cases. Mr Bush has, for the first time, admitted sending terrorist suspects abroad for interrogation, and authorities in Sweden, Italy and Germany are investigating alleged CIA kidnappings on their own soil.

Khalid el-Masri, a German national whose story is confirmed by German officials, says he was arrested on the Macedonian border on New Year’s Eve, 2003. After being held for three weeks by Macedonian officials who pressed him to admit that he was an al- Qaeda member, he was driven to Skopje airport, beaten, stripped, shackled and flown to Baghdad, and then to Kabul.

El-Masri says he woke in a jail cell and was told: “You’re in a country without laws and no one knows you are here.” After being held for five months in solitary confinement, he was flown back to the Balkans last May and dumped on a hillside, where Macedonian border guards returned his passport and cash.

German investigators have checked the flight logs of a US-registered Boeing 737, which show that it arrived in Skopje at 9pm on January 23, last year, leaving six hours later for Kabul via Baghdad.

El-Masri, whose lawyer believes was seized because his name is similar to an al-Qaeda member, provided German police with the same times and dates.

The jet is owned by Premier Executive Transport Services. A CBS 60 Minutes investigation found that it had made at least 600 flights to 40 countries since the World Trade Centre attacks, including 10 to Uzbekistan, 30 to Jordan, 19 to Afghanistan, 17 to Morocco and 16 to Iraq.

Abu Omar, a radical Egyptian cleric, said in a phone call to his wife, monitored by Italian police, that on February 17, 2003, he was snatched off a Milan street by two men, sprayed in the face with chemicals and taken to a US airbase in Italy before being flown aboard a Gulfstream jet to Cairo, where he was tortured and beaten. He has not been seen since.

Armado Sparato, an anti- Mafia prosecutor, served a warrant last week on the Italian commander of the airbase at Aviano, home to the US Air Force’s 31st Fighter Wing.

Between June 2002 and January this year, the jet made 51 visits to Guantanamo Bay and trips to Afghanistan, Morocco, Dubai, Jordan, Italy, Japan, Switzerland and Azerbaijan.

Rendition was begun under President Reagan but was used sparingly. After the September 11 attacks, Mr Bush gave the CIA wide licence to send terrorist suspects abroad without prior approval. Off the record, officials say that 150-200 suspects have been rendered since then.

Copyright 2005 Times Newspapers Ltd.