This dark tale took another twist yesterday as the CPS announced that, for now, no British spies will face charges over their alleged complicity in the torture of detainees.

However, the Metropolitan Police has decided that suspicions over UK involvement in rendition to and torture inside Libya are so serious they demand an immediate criminal investigation.

There may also be further criminal investigations into other allegations that have emerged recently. And for the first time we have an unequivocal finding by law enforcement agencies that Binyam Mohamed was held in Morocco between 2002 and 2004 and that, during his time there, he did face questions supplied by the British Security Service. These developments make the need for an independent judicial inquiry into torture more vital than ever.

Liberty has long campaigned for an investigation into whether the UK government was complicit in torture. We called for a fair and impartial inquiry, presented openly and transparently, and the coalition won praise for promising just that. But the devil was in the detail, and what we actually got was the embarrassment of the Gibson Inquiry.

Toothless and secretive, its evidence protocol was deeply disappointing - revealing the final word on what material could be made public would rest not with a Judge but with the Cabinet Secretary. It made clear that torture victims would not be allowed to question those allegedly complicit in their abuse - even via legal representatives. Faced with such a whitewash we - along with other organisations involved and the victims themselves - said we won't participate in the process.

News that there will be a criminal investigation into Britain's suspected involvement with torture under the Gaddafi regime is obviously most welcome. But criminal law is not the only avenue for righting grave wrongs in our democracy and a proper judicial Inquiry is key. This was one of the worst scandals of recent memory and it deserves better than a murky internal Cabinet Office review. The government is more than capable of setting up effective and independent investigations - consider the Leveson Inquiry into press practices or the Baha Mousa Inquiry into the use of banned interrogation methods by the MoD in Iraq. Why can't ministers do the same for victims of torture?

In the Gibson Inquiry's shadow comes the government's Justice and Security Green Paper, which proposes to shut down open justice forever. Ministers want to be able to use closed proceedings in civil claims where they feel disclosure might 'harm the public interest'. So the executive would be allowed to defend torture accusations without revealing information that might be crucial to a fair hearing, let alone the public interest in media scrutiny of alleged abuses of power. The victim bringing the claim would not even be present, and might never be shown the judgment. They might lose the case, but never know why.

It's bitterly ironic that the green paper also coincides with the tenth anniversary of the first detainees arriving at Guantanamo Bay. Our government is marking a decade of one of the worst excesses of post 9/11 policy not with more public scrutiny, but less. These proposals, if previously in force, would have prevented such unacceptable practices from ever being exposed as they were through litigation and investigative journalism.

It's one of the UK's fundamental constitutional principles that no-one - including the executive - is above the law. It's no exaggeration to say this green paper would change that forever; destroying centuries of fair trial protections and recasting the entire civil justice system in favour of the government.

As the government considers its next move on the Gibson Inquiry, let's hope our concerns have finally been heeded and that this inadequate sham will be transformed into something truly worthwhile rather than the waste of time and money it has so far promised to be.