Shutting them up. That’s what it’s about. The hangman’s drop, the crackle of the firing squad, and their secrets go to the grave.

Saddam Hussein didn’t get the chance to tell us about his dealings with the US and German companies who provided the gas he used on the Kurds. And now Gaddafi’s spymaster Abdullah al-Senussi will be shot in Libya before he has a chance to tell us about the cosy relationship he had with our Western security services when he liaised between his boss, the CIA and MI6.

Not surprising, is it – despite Amnesty’s outrage at the charade of a trial and the UN human rights office being “deeply disturbed” by the sentences – that the Brits and Americans have not batted an eyelid since Senussi, Gaddafi’s son Saif and a bunch of other regime cohorts were sentenced to death last week without defence counsel or testimony or documents or witnesses? All those secret nudge-nudge agreements between Gaddafi’s odious torturers and our intelligence services will remain safe for ever. So everything is hunky-dory. Thank God for Libyan “justice”.

Now, of course, these men are a most unsavoury bunch. Senussi himself is held responsible for the massacre of more than a thousand of Gaddafi’s political prisoners. But he and his successor, Moussa Koussa – who protests that he never tortured anyone and can now be found relaxing in his villa in Qatar because the Brits and Americans are grateful to him for fingering al-Qaeda agents in Africa – were among the most loyal of Gaddafi’s henchmen. If you sup with the devil, you have a good chance of dying with him – or, at least, after a “fair” trial. But justice à la Nuremberg is supposed to involve full disclosure of the crimes of the accused.

The trial run (in both senses of the word) was Saddam. The Iraqi dictator’s most monstrous crime was his gassing of the Kurds at Hallabja in 1988, which killed up to 5,000 men, women and children. Yet his 2005 Anglo-American show trial concentrated on the execution of 140 Shia men in the town of Dujail in 1982. Yes, yes, I know that’s an atrocity, but Hallabja was genocide. This focus allowed the careful avoidance of any cross-examination that would touch on how Saddam had acquired the gas to extinguish all those souls. One gas component company was based in New Jersey. By the time Saddam’s henchmen were questioned about Halabja, their boss had already been hanged.

Crimes against humanity certainly involved Abdullah al-Senussi, including the torture of Libyan exiles after their barbaric rendition to Libya with the help of MI6 and other Western agencies. He provided the reception party of thugs at the Tripoli end, and read the information they provided after torture. Human rights groups regarded Senussi as the “black box” recorder of the secret liaisons that began after Tony Blair so delicately kissed The Great Leader himself. Senussi knew far more about our spying agencies and their dirty tricks than Saif al-Gaddafi – the late Muammar’s son – who has also conveniently been sentenced to death. Maybe that’s why Senussi initially did a runner to Mauritania, which should have handed him over to The Hague. But after – according to Libyan parliamentarians – receiving a bribe of $200m, Mauritania returned him to Tripoli.

Once there, maybe Senussi did spill the beans about our dirty deeds. His daughter, Anoud, told me that when she saw her father in a Tripoli prison long before his trial, he had apparently been “beaten on the eyes and nose” and was very weak, weighing less than 35 kilos (about five and a half stone). “He had been threatened [that] he would be hurt if he spoke about his treatment.”

Where most executions were carried out in 2014 Show all 10 1 /10 Where most executions were carried out in 2014 Where most executions were carried out in 2014 1. China (1000+) Getty Where most executions were carried out in 2014 2. Iran (289+) Getty Where most executions were carried out in 2014 3. Saudi Arabia (90+) Getty Where most executions were carried out in 2014 4. Iraq (61+) Getty Where most executions were carried out in 2014 5. USA (35+) Getty Where most executions were carried out in 2014 6. Sudan (23+) Getty Where most executions were carried out in 2014 7. Yemen (22+) Getty Where most executions were carried out in 2014 8. Egypt (15+) Getty Where most executions were carried out in 2014 9. Somalia (14+) Getty Where most executions were carried out in 2014 10. Jordan (11+) Getty

So what had he been forced to tell his torturers then? And who, since we know that MI6 and the CIA write out the information they want from Arab torturers, composed the questions? Almost two years ago, Anoud told me that her father would not get a safe trial. She was right about that.

Senussi’s international counsel, Ben Emmerson QC, knew something was very wrong with the case when the International Criminal Court at The Hague first accepted that Senussi could be tried by the militia-haunted court in Tripoli. These custodians of the law did ask, however, for Saif Gaddafi to be sent to The Hague. Because he knew less?

Either way, they didn’t get their man. He was sentenced to death by the same kangaroo court as Senussi, via video link to the militia-controlled town where he’s been held since his capture in 2011. Emmerson told me in 2013 that when Senussi’s lawyers wanted to know if MI6 operatives had interrogated their client while he was in Mauritania – before his illegal rendition to Libya – William Hague, the Foreign Secretary at the time, declined to answer.

At the weekend, Ben Emmerson deplored the death sentence because Senussi had no legal representation, no access to his family, no ability to prepare his defence, and no possibility of challenging the prosecution. “The trial has been conducted in an atmosphere of extreme fear, insecurity and intimidation,” he said, “in which judicial officials and defence lawyers have been threatened and physically attacked.”

As another Brit who had tried long and hard to defend Senussi also said to me at the weekend: “All in the know are going to be shot.” Not that Gaddafi’s victims received better “justice”. But it was Blair who kissed the wretched man and David Cameron who helped to destroy him.