A human rights group has criticised the “smokescreen” surrounding the ongoing probe into CIA rendition flights landing at Scottish airports.
Amnesty International’s Naomi McAuliffe said “excessive secrecy” was “fuelling the national security threat”.
Police Scotland is investigating claims airports were used as stop-offs for planes transferring suspected terrorists to secret jails overseas.
The force said it could not comment on an ongoing investigation.
The current inquiry was requested by the Crown Office in mid-2013 after an academic study claimed that Aberdeen, Inverness and Wick and airports were used in the rendition of suspected terrorists.
The researchers, Dr Ruth Blakeley at the University of Kent and Dr Sam Raphael at Kingston University in London, claimed to have identified 13 planes, with links to the CIA operation, which had touched down at the airports.
The so-called extraordinary rendition programme operated for years in the wake of the September 11 attacks, and involved the secret detention and transfer of terror suspects to other countries for interrogation and alleged torture.
The study also identified the use of Prestwick, Glasgow and Edinburgh as fuelling stop-offs for these alleged rendition flights, often linking the US and the Middle East.
But 29 months on, it is unclear what headway Police Scotland has made in its ongoing investigation.
By comparison, a Finnish investigation into rendition flights lasted 19 months.
An initial investigation by Scottish police was previously conducted in 2007 and 2008 but the police concluded there was insufficient credible information to enable them to commence a criminal investigation.
Naomi McAuliffe, programme director of Amnesty International Scotland, said the latest probe was taking “a very long time” considering particular aircraft implicated in rendition flights had already been identified.
She said: “We’ve been working away at this for years ourselves, calling for an independent, judge-led inquiry and we keep on coming up against the same kind of stumbling blocks, of national security being used.
“We really see that as being a smokescreen for getting this information out.
“The national security issue that might happen is that people suspect that rendition flights went through Prestwick airport for example – [but] that suspicion is already out there.”
And national security was one of the reasons why Police Scotland refused to issue a redacted version of its 2014 interim report on the current probe to the Crown Office – a decision which was backed by the Scottish Information Commissioner upon appeal after a seven-month battle for the document.
Although the BBC argued the Scottish public were entitled to know whether adequate progress had been made towards determining whether or not their skies had been implicated in flying people to detention without trial, the commissioner ruled that the release of the report could have an impact on a live investigation.
However, a separate freedom of information request revealed that the force made no attempt at all to redact the document, claiming “it was not possible to negate the perceived harm via redaction of the report”.
The Crown Office also refused to release a summary of the report, to indicate when it was received from Police Scotland, or even how many pages long the document was “to avoid the risk of prejudicing this investigation”.
A follow-up freedom of information request for all the police’s email correspondence related to BBC Scotland’s original request for the interim report, was also denied on the grounds the “frank exchange of views would be substantially inhibited”.
A further request by BBC Scotland revealed that, as of December 2014, only two officers had been allocated to the investigation, and Police Scotland was unable to report how many man hours had been spent on the inquiry.
Ms McAuliffe said the lack of transparency could, ironically, itself pose a terrorist threat.
She said: “Already there is a suspicion that the UK was involved in rendition and in torture.
“If we’re able to bring people to account for this, actually put people on trial, find out if in fact this had taken place, then we can have some accountability for it.
“Just having this suspicion in itself is a risk – people already think internationally that the UK has been involved in torture and therefore is a target because of that.”
But Ms McAuliffe said there may be other implications which have led to a delay in releasing any findings in the Scottish investigation.
She said: “They could be hiding that there may not have been proper procedures in place, that if these flights were landing, were they being properly investigated, were they being searched?
“If it actually turns out that these were landing here but we didn’t know who was on board, that in itself has implications for the processes that airports are using.
“If they did know about it, they were colluding in torture which actually means we have gone against international treaties that we’ve signed up to and our own domestic laws as well.”
Vital US document
In December 2014, the US Senate issued a 500-page report on the existence of a network of CIA torture prisons – known as black sites – from Thailand to Poland, to the notorious Guantanamo Bay in Cuba.
Lord Advocate Frank Mulholland subsequently instructed Police Scotland to consider this report on the CIA’s treatment of al-Qaeda suspects as part of its current probe into rendition flights.
In May, the Crown Office confirmed it had instructed police to request and consider the full version of the report, thought to be more than 6,000 pages.
But despite the initial request for the report, five months on, both Police Scotland and the Crown Office have refused to say whether the report has now been handed over to them.
Both bodies also refused to comment on the length or progress of their investigation, or what co-operation they had received from the US government.
Det Ch Supt Gerry Mclean, from the Organised Crime and Counter Terrorism Unit, said: “As Police Scotland is currently carrying out a live investigation on the instruction of the Crown Office, it would be inappropriate to comment further at this time.”
BBC Scotland also contacted the Foreign Office, Downing Street and Westminster’s Intelligence and Security Committee – all refused to acknowledge whether a full copy of the US Senate’s report had been requested or received.
Donald Campbell, from human rights organisation Reprieve, expressed concern over the lack of apparent progress by Police Scotland.
He said: “It is vital that the police investigation gets to the bottom of the involvement of Scottish airports in the CIA torture flights programme, but it is hard to see how this will be possible if they are denied evidence that could prove crucial.
“We need to know whether the police have been given access to the full, uncensored version of the US Senate torture report.
“If not, the Scottish and UK governments need to take the matter up with the US, and ensure that investigators are given the access they have asked for.”
Liberal Democrat MSP Tavish Scott, who tabled a number of rendition-related questions before parliament earlier this year, also called for a progress report.
He said: “I’m not sure why the Scottish government can’t tell Police Scotland to let us know what’s going on here, to keep us up to date with a really important issue that people care about.
“Flights were landing in Scotland taking people to hellholes around the world where they’ve been tortured – I think Scottish people deserve some answers to that.”
However a Scottish government spokesman said the ongoing police investigation “must be allowed to run its course”.
“In terms of any material relating to rendition flights and any use of facilities in Scotland, the Scottish government would welcome full disclosure of all relevant facts at the appropriate time,” the spokesman said.
Meanwhile a recent newspaper article claimed that a number of planes linked previously to the CIA’s “torture flights” have continued to land at Prestwick airport since the Police Scotland investigation began.