David Cameron was last night under intense pressure to deliver on his promise to hold a judge-led inquiry into British complicity in torture.

As the clamour for an independent investigation mounted, the Prime Minister was condemned for insisting a Westminster committee should do the job even though it presided over an alleged whitewash in the treatment of terror suspects.

An alliance of nine human rights groups said only a judicial probe could get to the truth of the disturbing questions raised by an explosive US Senate report which laid bare the barbaric treatment of detainees by the CIA.

In a letter to Downing Street, seen by the Daily Mail, the organisations blasted the Premier’s decision to allow Parliament’s Intelligence and Security Committee (ISC) to investigate the UK’s ‘shameful’ involvement in American wrongdoing.

David Cameron was last night under intense pressure to deliver on his promise to hold a judge-led inquiry into British complicity in torture. Pictured: Guantanamo Bay

Nine human rights groups told David Cameron only a judicial probe could get to the truth of Britain's role in torture by the CIA

It said the ISC was inadequate to look into allegations that, during the war on terror, British agents colluded in extraordinary rendition – where suspects are moved to secret prisons around the world for torture – and turned a blind eye to abuse of captives.

The joint letter was sent to Number 10 as the spotlight once again fell upon the case of Shaker Aamer, the British resident who has been held in Guantanamo Bay for almost 13 years.

US President Barack Obama said holding people in the camp ‘continues to inspire jihadists around the world’. Over the weekend, four Afghans were sent home leaving around 130 detainees, including father of four Mr Aamer.

Mr Cameron has been under growing pressure to order a judge-led inquiry since the Senate intelligence committee report earlier this month detailed CIA beatings, waterboarding, hanging and the rectal feeding of detainees.

But it had been stripped of any mention of the UK security services or Diego Garcia, the British territory in the Indian Ocean that Labour admitted was used for at least two US rendition flights.

Shaker Aamer, the British resident who has been held in Guantanamo Bay for almost 13 years

MI6 agents have also been accused of being present when terror suspects were tortured. Compelling evidence has also emerged that Diego Garcia was used to hold prisoners.

The letter, signed by human rights charities including Reprieve, Liberty and Amnesty International, said neither the ISC inquiry, nor its predecessor, begun by Sir Peter Gibson but controversially axed by the Government last year, ‘came up to the mark’.

It said Mr Cameron had shamefully ‘U-turned’ on his 2010 vow to hold a judge-led inquiry to probe into the sickening abuse claims. At the time, the Prime Minister said the ISC could not be independent and would not inspire public confidence.

The ISC cleared MI5 and MI6 of involvement in extraordinary rendition in 2007.

The letter said: ‘The publication of the report by the Senate Select Committee on Intelligence has highlighted not only the horrors of the CIA’s torture programme, but also the UK’s failure as a country to put our own house in order. We therefore urge you to deliver on your promise of an independent, judge-led inquiry with the powers necessary to get to the truth, before next year’s General Election.’

Last night, President Obama said he remained committed to trying to close Guantanamo Bay by 2016. That would mean finding a solution to the wrangle over Mr Aamer who the authorities wish to send to his native Saudi Arabia, even though his British family live in South London.

A British soldier was investigated for possible war crimes for simply thrusting a piece of paper at a Taliban fighter, it has emerged.

He was accused of abuse for touching the terror suspect on the nose with the sheet during a routine interrogation in Afghanistan. The fighter was suspected of being a potential ringleader in the murder and mutilation of four French soldiers in 2008.

But it was the intelligence officer – who had an exemplary record – who ended up being investigated amid claims that he had broken rules banning the touching of prisoners during interrogation.

And another interrogator was probed for shouting in a suspect’s ear, it was claimed.