Blair and PM David Cameron meet at Downing Street, last year
Cameron must hold full investigation into Britain's alleged complicity in torture during Tony Blair's tenure

On Tuesday, the Senate Intelligence Committee exposed the full extent and brutality of CIA torture, showing that these practices are more than just abhorrent – they're ineffective too. By publishing its report, the Committee has rightly dragged this darkest of scandals into the light – and now our own authorities must do the same.

The report is heavily redacted and contains no details of UK involvement in CIA torture and rendition. But now that the US has revealed its gruesome secrets, our government's excuses for dodging a fair, thorough and independent investigation into UK complicity look even flimsier than before. America knows the truth – it's time we did too.

Throughout the 'war on terror', the UK Government repeatedly attempted to sidestep, ignore and undermine our legal and moral obligations to prevent torture. Liberty first raised concerns about our country's role in extraordinary rendition in 2005, calling on police to investigate.

We now know that UK airspace and territory was used for rendition flights. We know that our forces handed over individuals in Iraq to US authorities, who then illegally rendered them to an Afghan prison known for its inhuman conditions. We know our security services helped US authorities interrogate former Guantanamo Bay detainee Binyam Mohamed, even though they were aware he was being detained in cruel and degrading conditions.

In short, we know the UK was complicit in torture and kidnapping, but we just don't know the extent – and nobody has been held to account.

Yet nearly a decade on there's no sign of the independent, judicial inquiry we urgently need. Instead we've witnessed 10 years of flim-flam and broken promises. In 2010 the Prime Minister promised an inquiry. What we ended up with, the Gibson "Inquiry", was a sham – no more than a secret internal review with the Government pulling the strings.

When the then-Justice Secretary Ken Clarke scrapped it in 2012, he repeated the pledge. Then, in another U-turn, the task was handed to the Intelligence and Security Committee (ISC) – which is made up of MPs and peers nominated by the Prime Minister.

Responding to the CIA torture report, David Cameron said: "In Britain we have had the Gibson Inquiry and that inquiry has now produced a series of questions that the Intelligence and Security Committee will look at, but I am satisfied that our system is dealing with all of these issues."

But to anyone committed to democratic values, such as fairness, justice and rule of law, that system is anything but satisfactory. Not only are ISC members approved by Mr Cameron, everything they publish goes through him. It's also the same committee which, in 2007, speciously reported that there was no evidence of UK involvement in extraordinary rendition.

Guantánamo Bay
Prisoners at Guantánamo BayYoutube

The British public deserve more than a whitewash – and victims of torture deserve their day in court. Anyone, anywhere, who was involved in ordering, sanctioning or carrying out torture must face prosecution. But until our Government establishes a proper investigation, cover-up and official impunity will persist.

There can be no compromise with torture. Under no circumstances should it ever be justifiable for one person to torture another. By involving ourselves in it in any way, we make a mockery of our status as a civilised country and lose any ability to press other countries to respect human rights.

Now's the time for the Government to follow the US into the light, and do more than just condemn these horrendous abuses but pledge to get to the truth of our role, find those responsible and hold them to account. It's certainly not the time to furnish our Agencies with greater powers to leave Britons vulnerable to torture abroad – yet that's exactly what the Government's proposed power of exile in the new Counter-Terror Bill will do.

By laying bare the UK's involvement in this disgraceful chapter of the 'war on terror', with the full, transparent scrutiny of a judicial inquiry, the Prime Minister can begin to restore our country's reputation for respect for human rights and the Rule of Law. By failing to follow in the USA's footsteps, and continuing to look the other way, he risks staining it forever.

Isabella Sankey is director of policy at Liberty, overseeing parliamentary campaigning and policy development for one of Britain's biggest human rights groups. Visit the Liberty website for more info on their work and campaigns.