Report by ITV News International Affairs Editor Rageh Omaar
A government attempt to block a damages claim by a Libyan dissident and his wife against former foreign secretary Jack Straw has failed at the Supreme Court.
Abdel Hakim Belhaj and his Moroccan wife Fatima Boudchar, say they were tortured after their kidnap during Colonel Gaddafi's regime, and allege that the UK government was complicit.
They also name Sir Mark Allen, MI6's counter-terrorism chief at the time they were snatched in 2004, and are also claiming against the Home Office and Foreign Office.
The couple have offered to settle for a token amount of £1 and an apology and admission of liability for what they suffered. Liability is denied.
Their lawyers argue that they were victims of a secret rendition in a joint MI6/CIA operation, and are entitled to justice for "abuse at the hands of our government".
Government lawyers had argued that the claims should be barred under state immunity and the "act of state" doctrine, which prohibits the courts of one country judging the acts of the government of another within its own borders.
The High Court agreed with the government's stance and said the claims should be struck out.
However, the Court of Appeal reversed the High Court ruling in October 2014, saying the act of state doctrine may not apply to alleged breaches of human rights obligations or international law.
This may be the case even where the court is required to conduct an investigation into the validity of the conduct of a foreign state.
The appeal judges said there was "compelling public interest" in allegations of unlawful rendition, and "particularly grave violations of international law and human rights" being investigated by English courts.
Now seven Supreme Court justices have upheld that decision, and the action can go to trial.
Sapna Malik, of law firm Leigh Day which is representing Mr Belhaj said: "The Supreme Court today has delivered an emphatic judgment upholding the rule of law, particularly in the face of breaches of rights recognised as fundamental by English statute and common law, in which British defendants are alleged to have been complicit.
"The justices have clearly declared that the UK courts must not refrain from deciding such cases which may involve criticism of the conduct of foreign states, even when that foreign state is the US.
"We hope that the defendants in this action now see fit to apologise to our clients and acknowledge the wrongs done, so that they may turn the page on this wretched chapter of their lives and move on."
Then-Foreign Secretary Jack Straw said in a statement: "This judgment is about some important points of law, related to how far it is possible to bring into a court process in the UK actions of sovereign states abroad.
"However, at no stage so far have the merits of the applicant's case been tested before any court. That can only happen when the trial of the action itself takes place.
"I repeat what I said in the House of Commons in December 2013, that as Foreign Secretary I acted at all times in a manner which was fully consistent with my legal duties, and with national and international law.
"I was never in any way complicit in the unlawful rendition or detention of anyone by other states. "
Cori Crider, a lawyer from human rights organisation Reprieve, said the ruling was significant because of the president-elect's apparent willingness to use torture like waterboarding in future.
She said: "In 72 hours, a would-be torturer will take the reins of Earth's most powerful security state. So this case isn't 'just' about history - the stakes couldn't be higher.
"We enter the Trump era with not a soul held to account for Britain's past role in rendition. No official has condemned Trump's torture boasts. Our intelligence agencies may well be pressured to help America torture again.
"The Government bought years of delay by wasting hundreds of thousands of pounds on this appeal, when a simple apology would have closed the case. Theresa May should apologise to this family, draw a line in the sand against torture and restore British honour once and for all."
A government spokesperson said: "The Government notes the Supreme Court’s judgment on preliminary points of law in the Rahmatullah/Belhaj case. We will now consider the detail and implications.
"It would be inappropriate for the Government to comment further on this case due to the ongoing legal proceedings.