Soon after the Al-Qaeda attacks in America on September 11, 2001, I interviewed Porter Goss, a congressman who chaired the House intelligence committee and would later be director of the CIA. I asked him if there had been any plan to kidnap Osama Bin Laden.

“It’s called a rendition. Do you know that?” said Goss.

“No,” I admitted.

“Well, there is a polite way to take people out of action and bring them to some type of justice.”

Under traditional American justice, rendition meant capturing wanted people abroad and bringing them to trial in US courtrooms. But, as I subsequently discovered, a policy of “extraordinary rendition” had been invented under President Clinton in about 1995. In secret, the CIA had rendered suspects not to America but to foreign countries such as Egypt, Jordan, Algeria and Morocco.

After 9/11 such outsourcing had expanded dramatically. When the Guantanamo camp opened in Cuba, a CIA source described it as the Pentagon’s “press release” — what Washington wanted the world to see. Beyond it there was a larger netherworld of secret prisons or “black sites” involving hundreds more prisoners. Even Uzbekistan, known for boiling prisoners alive, and Syria, with its infamous “German chair” designed to twist a victim’s spine, now secretly hosted America’s detainees.

Many of those transferred were genuine terrorists who posed a threat. But in a process without legal controls, among them, too, were innocents. A Canadian, Maher Arar, seized at JFK airport in New York in 2002 and sent to Syria, was not only tortured but held for 10 months in a cell barely larger than a coffin. Ultimately he would be cleared by an official Canadian inquiry of terrorist connections.

When I penetrated this secret world, I found that the CIA had left some obvious clues. A CIA airline linked the black sites; and, in defiance of good tradecraft, the airline had over nearly four years used the same planes, with the same registration numbers, to carry out its renditions. This meant that by tracing the records from air traffic control of these particular planes, I could obtain a kind of ledger of the CIA’s activities.

The flight logs showed the insertion by the CIA in November 2001 of undercover teams to Afghanistan. They showed flights in 2003 to Libya, joined by Britain’s MI6, to negotiate with Colonel Gadaffi. But above all they showed renditions — flights from Morocco to Kabul that matched the exact description provided by prisoners such as Binyam Mohamed, a young Ethiopian brought up in Golborne Road, west London, and educated at Paddington Green College.

Mohamed had travelled from Britain to Afghanistan in July 2001 in search of militant training. He escaped when the Americans invaded after 9/11 but was arrested in Pakistan as he boarded a plane to London.

He was accused of being the accomplice of José Padilla, the former Chicago street gangster who was said to have plotted to explode a radioactive device in the United States.

A few weeks later Mohamed was sent on a CIA jet to the Moroccan capital where he alleges he underwent weeks of torture, including being beaten, cut with razors and drugged. He was taken 18 months later to Afghanistan. Flight logs show his flight on “Rendition Air”.

On the evening of January 22, 2004 a Boeing 737 executive business jet landed at Palma airport in Majorca and taxied to a small business terminal. The captain and his four crew gave false names and used false US passports. All were operatives from the modern version of what was once called “Air America”, the CIA’s secret Vietnam-era airline.