Amal Clooney is about to take on one of her biggest legal challenges yet - accusing the British government of committing torture in Troubles-era Northern Ireland, then then lying about it to the European Court of Human Rights.

The accusations will be levelled in a high-profile case due to come before the Strasbourg Court. The outcome could rewrite the law books and help to combat the use of torture globally.

Here’s what happened. In August 1971 the UK authorities arrested and interned hundreds of men in Northern Ireland. Fourteen were selected for “special treatment" in a specially-built interrogation centre at a British Army camp.

The men claim they were subjected to “five techniques” of hooding, stress positions, white noise, sleep deprivation and deprivation of food and water - combined with brutal beatings and death threats. Some were also reportedly thrown from helicopters while their heads were covered with hoods.

Allegations soon emerged of abuse. In the same year, Amnesty International sent its first ever research mission to the UK to investigate, interviewing the men and finding some of them still black and blue with bruises.

What Amal Clooney - who has just joined the legal team representing the surviving men - must prove, is that the abuse amounted to torture, rather than the lesser category of “inhuman and degrading treatment”. The distinction is crucial.

CIA torture report: The 10 most harrowing stories Show all 10 1 /10 CIA torture report: The 10 most harrowing stories CIA torture report: The 10 most harrowing stories CIA torture report 1. Of the 119 CIA detainees, 26 should not have been apprehended. Among them was Abu Hudhaifa, who was “subjected to ice water baths and 66 hours of standing sleep deprivation” before the CIA discovered that he was probably “not the person he was believed to be.” CIA torture report: The 10 most harrowing stories CIA torture report 2. President Bush received his first briefing on enhanced interrogation techniques in 2006, about four years after the programme started. According to CIA records, Bush expressed discomfort with an image of a detainee “chained to the ceiling, clothed in a diaper.” CIA torture report: The 10 most harrowing stories CIA torture report 3. The CIA used rectal feeding and rectal rehydration on at least five detainees. Even though detainee Majid Khan was cooperating with feedings, for example, the CIA subjected him to “involuntary rectal feeding and rectal hydration” and would puree his lunch tray, which was then “rectally infused.” CIA torture report: The 10 most harrowing stories CIA torture report 4. CIA interrogators threatened to harm the family members of at least three detainees. In one case, a detainee was told that his mother's throat would be cut. CIA torture report: The 10 most harrowing stories CIA torture report 5. The CIA apprehended two foreigners working for a “partner government” allied with the agency. They were subjected to sleep deprivation and dietary manipulation. The two detainees were trying to give the CIA information on possible future al-Qaeda attacks. It took them months to get released. CIA torture report: The 10 most harrowing stories CIA torture report 6. Abu Zubaida, the CIA's first detainee, spent 266 hours in a coffin-size confinement box. Zubaida, who was born Zayn al-Abidin Muhammed Hussein, often “cried, begged, pleaded, and whimpered” and was told that the only way he would leave the facility was in the coffin-shaped box. CIA torture report: The 10 most harrowing stories CIA torture report 7. When Khalid Sheik Mohammed, who was waterboarded 183 times, tried to breathe during the procedure, interrogators held his lips and poured water over his mouth. CIA torture report: The 10 most harrowing stories CIA torture report 8. The Senate committee found a photo of what looked like a well-used waterboarding station at a site where there was no reported use of the technique. The CIA could not explain the presence of the waterboard. CIA torture report: The 10 most harrowing stories CIA torture report 9. Of the at least 26 detainees who were wrongfully held, one was “intellectually challenged.” Interrogators taped this detainee crying and used it as leverage against one of his relatives. CIA torture report: The 10 most harrowing stories CIA torture report CIA officers would “strip a detainee naked, shackle him in the standing position for up to 72 hours, and douse [him] repeatedly with cold water.”

The original case was brought by the Irish government on behalf of the men, the first time one European state had brought another before the Strasbourg court. In 1978 the court concluded that the “five techniques” inflicted on the men constituted inhuman and degrading treatment in breach of Article 3 of the European Convention of Human Rights, but not torture.

The judgment has since become a cornerstone of international human rights law. So much so, that when lawyers in the United States Attorney General’s office prepared legal advice to pave the way for the CIA’s “enhanced interrogation programme”, they reached for the Ireland v UK case, arguing that its judgment allowed “an aggressive interpretation as to what amounts to torture”.

With the publication in December of the Senate Committee’s summary Torture Report, the world has seen where that legal reasoning led: the brutal torture of detainees around the world and irreparable damage to the reputation of the US.

All this came to pass, it is now alleged, because the British government of the time decided to withhold documents from the European Court of Human Rights, rather than be reviled internationally for the torture of its own citizens in Northern Ireland.

Twelve of the original "hooded men" who are being represented by Amal Clooney

The “hooded men” case is now being brought back to court by Ireland’s government after material was uncovered in the British national archives revealing that the UK withheld crucial evidence from the European Court during the original hearing.

The files show that the British government considered the “special treatment” as torture and yet senior Ministers sanctioned its use in Northern Ireland, both of which they had denied before the European Court.

Amal Clooney and the rest of the hooded men’s legal team now must show that the UK only succeeded in persuading the court to absolve it of torturing its own citizens by actively misleading judges.

More serious charges could scarcely be made: torture, and lying to the European Court. If Ireland, the hooded men and Amal Clooney succeed with this case, the implications are potentially huge.