A former CIA operative is to be the first to be extradited to face court over the Bush administration's heavily criticised policy of kidnapping terror suspects and smuggling them to third countries for interrogation.

In the latest twist in a decades-long transatlantic espionage scandal, the Portuguese Supreme Court has upheld a request from Italy to extradite Sabrina de Sousa, who was detained in Lisbon last year.

Ms de Sousa, 57, has already been convicted in absentia for her alleged role in the CIA kidnapping of Abu Omar, a Muslim cleric accused of jihadist sympathies. He was seized in broad daylight from a Milan street, flown to Egypt and handed over to the authorities there who are said to have jailed and tortured him for four years before releasing him without charge.

The development sets the stage for a high-profile trial in Italy that could reveal new details about the CIA’s secret transfer and detention of terror suspects between countries in Europe under the so-called extraordinary rendition programme that operated for years after the 9/11 attacks.

“This gives me the chance to finally clear my name after a decade of legal jeopardy that made it nearly impossible to expose a cover up,” Ms de Sousa told the Telegraph from Lisbon.