THE UK tolerated "inexcusable" treatment of detainees by the US during the war on terror following the 9/11 attacks in 2001, a Westminster committee has found.

The Intelligence and Security Committee[ISC] found no "smoking gun" indicating that security and intelligence agencies had a policy of deliberately overlooking reports of mistreatment and no evidence that UK officers directly carried out physical mistreatment of detainees.

But it said it was "beyond doubt" that British intelligence agencies knew at an early stage that the US was mistreating detainees.

And the report found "more could have been done" by both security agencies and UK Government ministers to try to influence the American Government’s behaviour.

Labour said the ISC's conclusions meant a judge-led inquiry into claims of torture and rendtion was now "inescapable".

The report found that in 232 cases British personnel continued to supply questions or intelligence to allies after they knew or suspected mistreatment.

And in 198 cases, they received intelligence obtained from detainees who they knew or should have suspected had been mistreated.

There were at least 38 cases in 2002 alone of British officers witnessing or hearing about mistreatment.

The Committee rejected agencies' claims that these amounted to no more than "isolated incidents", stating: "They may have been isolated incidents to the individual officer witnessing them but they cannot be considered 'isolated' to those in Head Office.

"It is difficult to comprehend how those at the top of the office did not recognise the pattern of mistreatment by the US.

"That the US, and others, were mistreating detainees is beyond doubt, as is the fact that the Agencies and Defence Intelligence were aware of this at an early point."

Earlier this year, Scottish authorities were accused of dragging their feet in a five-year investigation into CIA “extraordinary rendition” flights; the practice of moving suspects between countries without judicial oversight.

In 2013, Frank Mulholland, the then Lord Advocate, ordered an inquiry into rendition stopovers in Scotland.

Following the 9/11 terror attacks The Herald revealed that an aircraft linked with prisoner transfers - the so-called Guantanamo Bay Express – had stopped at Prestwick.

In 2014, it was suggested police were investigating at least six stopovers; four at Prestwick and two at Glasgow Airport.

Earlier this year, Police Scotland and the Crown Office described the investigation as “ongoing”.

Today’s parliamentary report found three cases when MI5 or MI6, the Secret Intelligence Service[SIS], made or offered payment towards the "extraordinary rendition" of detainees to states where they were under real risk of torture or cruel, inhuman or degrading treatment.

In 28 cases, UK agencies suggested, planned or agreed to rendition operations, in a further 22 SIS or MI5 provided intelligence to enable a rendition operation and in 23 more they failed to take action to prevent a rendition.

The report also found evidence of UK officers making verbal threats in nine cases, as well as two cases in which UK personnel were party to mistreatment administered by others.

One of these has yet to be fully investigated and the committee raised the question of whether it should now be reopened.

There was no evidence that any US rendition flight transited the UK with a detainee on board but two detainees are known to have transited through the Indian Ocean UK territory of Diego Garcia, where records of the conditions under which they were held are "woefully inadequate".

"In our view the UK tolerated actions, and took others, that we regard as inexcusable," said Dominic Grieve, the Committee Chairman.

"That being said, we have found no 'smoking gun' to indicate that the agencies deliberately overlooked reports of mistreatment and rendition by the US as a matter of institutional policy.

"The evidence instead suggests a difficult balancing act: the agencies were the junior partner with limited influence and concerned not to upset their US counterparts in case they lost access to intelligence from detainees that might be vital in preventing an attack on the UK."

Mr Grieve, the former Attorney General, acknowledged the pressure the agencies were operating under at a time when they feared an attack on the scale of 9/11 could be imminent in the UK.

"We wish to be absolutely clear that we do not seek to blame individual officers acting under immense pressure.”

But he added: "More could have been done at an agency and ministerial level to seek to influence US behaviour. More could also have been done to distance themselves from mistreatment of detainees."

In a three-year inquiry, the ISC reviewed 40,000 documents and interviewed former detainees and three ex-officials but it was denied access to intelligence officers who were involved in the events.

Mr Grieve said the Government's refusal to allow agents to give oral evidence forced the committee "reluctantly" to cut its investigation short.

No 10 said it was not normal procedure for junior officers to be cross-examined by the committee and insisted that the Government had fully co-operated with the ISC.

But Labour's Shami Chakrabarti said: “It is now clear from the published reports that the ISC denied access to individuals, severely limiting its ability to give as comprehensive a resolution to this scandal as it would have liked.

"Its criticisms of ongoing inadequacies on guidance relating to torture and rendition also makes a judge-led inquiry - that the Government is so keen to avoid - inescapable,” insisted the Shadow Attorney General.

In a separate report on current practices, the Committee said it was "astonishing" that, after more than a decade of controversy, the Government had still not established a clear policy on rendition. It gave ministers a three-month deadline to publish a policy.

The failure to ensure that allies could not use UK territory for renditions without prior permission and the reliance on retrospective assurances from the US administration was "completely unsatisfactory", particularly in the light of the "clear shift in focus" of US policy under President Donald Trump.

Mr Grieve said it was "nonsensical" for the Government to argue that rendition could not be included in the formal list of cruel, inhumane and degrading treatments because it was too difficult to define.

New guidance introduced seven years ago to govern security agents' approach to detainees overseas was used a total of 2,304 times between 2013 and 2016.

The report found no instances of a deliberate breach of the guidelines.

But the ISC voiced "concern" that there was no record of the number of times cases were referred up to ministers because of a serious risk of mistreatment.

It called for a full review of the guidelines to make clear that no official should be able to authorise action where there was a serious risk of torture.