The stock justification for the injustices committed in the pursuit of the war on terror is that they are an inescapable necessity: the need to pre-empt potential or aspiring terrorists from executing their vile ideas is so great that it takes precedence over their human rights and the rule of law.

By seeking to deny their victims the rights they enjoy themselves, runs the logic, these reprobates have forfeited any claim to normal justice. Such is the danger they pose to society that they have to be neutralised at source. They are sub-human and must be treated according to the same sub-human standards they set for their victims.

This is the attitude that has informed US and European policy since the attacks of 11 September 2001. And by and large, it has been accepted without much opposition. The fear and loathing engendered by terrorism carried out in the name of Islam, and deliberately exacerbated and exploited by western states, has caused them to abandon the natural caution and distrust with which they view the state’s executive branch. Despite the voluminous evidence that now exists to show how states have used the war on terror to increase their powers and attack civil rights, there is little public appetite to challenge their excesses.

The attenuation of our basic legal and democratic rights - some of the most ancient principles enshrined in the Western legal tradition - has been one of the biggest prices exacted by the war on terror: habeas corpus, freedom of movement and the right to life itself have all been sacrificed at its unholy altar. Terrorism has come to be seen as a crime apart meriting lesser human rights safeguards for suspects than other crimes. Why should this be case? For all the revulsion and outrage they provoke, there is no parallel political desire to reduce the human rights of other categories of criminals such as child rapists or serial killers.

Whilst many states have been complicit in the rollback of our fundamental rights, it is the United States which has spearheaded the assault. Even before George W Bush had uttered the phrase “war on terror” in September 2001, his predecessor Bill Clinton had “rendered” some 70 al-Qaeda suspects to the US and other mainly Middle Eastern dictatorships that had outstanding proceedings against them and where, despite diplomatic assurances to the contrary, it was known that they would be tortured. However, despite its infractions, the Clinton administration was at least anxious to maintain the illusion of due process and legality. Clinton’s renditions took place in accordance with the law of the states from which they were rendered and the countries that received them.

But after the attacks of September 2001, even this veneer of legality was abandoned. George W Bush gave the CIA carte blanche to round up al-Qaeda suspects, often on the flimsiest of evidence, giving rise to the term “extraordinary rendition' - extraordinary because the policy entailed the deliberate violation of legal norms and individual rights.

Under the policy CIA operatives, with a willing hand or blind eye from their allies in the Muslim world and Europe, were able to abduct suspects from states, usually with but sometimes without those states’ knowledge, and shipped off to the US concentration camp in Guantanamo Bay or countries where they would be subjected to equally inhumane and degrading treatment and be denied the most basic legal rights.

In 2003, in the Italian city of Milan, Hassan Mustafa Osama Nasr, better known as Abu Omar, was snatched off the street by American agents in broad daylight, beaten, bound and gagged and tortured before being repatriated to his native Egypt. Here he would be brutally tortured for months whilst he was interrogated.

The abduction came as a shock to Italian law enforcement officials who had had Abu Omar under surveillance for some time and were close to making an arrest. Abu Omar was a veteran of the wars in Afghanistan and Bosnia and had also spent time in Yemen. Whilst in Italy, the Muslim cleric was suspected of recruiting mujahideen to fight the US-led occupation of Iraq.

As Italian police pieced together the movements of their vanished quarry their findings soon led them to a brazen American-Italian plot involving dozens of spies to snatch Abu Omar. Led by a determined magistrate called Armando Spataro, police began the task of  bringing Abu Omar’s kidnappers to justice, a process that ended in 2009 when 23 US nationals, all but one of them CIA agents, were convicted in absentia for their part in the rendition. The group included then head of CIA operations in Milan, Robert Seldon Lady.  Of nine Italian nationals indicted by Spataro, only two were convicted. Two accepted a plea bargain and five including then chief of Italian intelligence Nicolo Pollari, and Jeffrey Castelli, the CIA chief for Rome, could not be prosecuted owing to diplomatic immunity.

The convictions represented the first successful prosecution by a country of the US policy of extraordinary rendition. Germany had also issued warrants for US agents in the case of one of its citizens Khaled el-Masri, abducted mistakenly whilst on holiday in Macedonia and flown to Baghdad and then Afghanistan to be interrogated under torture. El-Masri’s only crime was to share the same surname as an al-Qaeda suspect in the Hamburg cell that produced the 9/11 attackers. However under pressure from the US, German officials never issued international warrants to extend the domestic arrest warrants issued by a Munich court in 2007 for 13 Americans suspected to have taken part in the kidnapping.

In September 2012 following an appeal by the convicted men the Court of Cassation in Italy upheld all the original verdicts and also ordered the trial of the men who had escaped prosecution on the grounds of diplomatic immunity. The result is highly significant for it remains the only successful application of European laws against extraordinary rendition. Until public pressure forced European Union member states to come clean about their level of involvement they had either acquiesced or complied with the CIA in rendering terrorism suspects to third countries. In the case of Abu Omar the CIA agents were so confident of immunity from prosecution by the Italian state that they did not even bother to cover their tracks.  Finally, in 2007, a Council of Europe report admonished no fewer than 15 member states plus Turkey for helping the CIA carry out over 1000 undeclared flights on their soil.

The Abu Omar case shows that where the judicial will exists the law is an important tool against state abuse of power and the last line of defence for our cherished freedoms and rights. It is a reminder to democratically elected governments that they remain accountable and should not consider themselves above the law. None of the 23 Americans are likely to serve their sentences unless they travel to Europe and are arrested, but the case is nevertheless a sobering lesson to the US that it cannot strut around the world acting as some kind of Robocop. Doing so simply breeds more resentment against the US, which is exactly what happened in Iraq. “We make a big gift to the terrorists when we behave contrary to our democratic principles,” Spataro said. “We give to those fish other water to swim.”