I HAVE, as our American friends sometimes say, a dream.

In my little reverie, two of Glasgow's finest one day turn up at the headquarters of the CIA in Langley, Virginia, and ask to have a word with whoever is claiming to be in charge that week. For the sake of good taste, neither copper will say: "There's bin a torture."

After all, the reality of the allegations involving CIA rendition flights and Scottish airports does not approach even black comedy. The world's most powerful country stands revealed, in a vast report from its own Senate, as a torture state. That's not how America likes to see itself. On this side of the Atlantic, numerous politicians have issued denials of complicity which turn out to be - for how dare we say more? - "untrue". And then there's little Scotland.

Inevitably, the security establishment in the United States - and in London, for that matter - will treat that detail as an actual joke. The contempt shown to Scotland's legal system during the Lockerbie shambles ought to have been evidence enough that in those circles we don't count for much. But the fact does not oblige us to remain silent, not where grotesque violations of human rights and international law are concerned.

Those sleek, mysterious private jets turning up everywhere from Prestwick to Wick were not secrets for long. The CIA's rendition flights, "black sites" and outsourcing of torture when Dick Cheney was pulling the strings for George W Bush were all documented, to a degree, before the Senate set to work. The politicians, in the US, Britain and beyond, simply responded with unrelenting, blanket denials. Legislatures were kept - no pun offered - in the dark. Thus was democracy defended.

This was not a failure of journalism, or of honest politicians. As long ago as 2005, my colleague Neil Mackay was describing the operations of a global torture industry in harrowing detail, telling of 75 flights through Prestwick, almost as many through Glasgow, and of 20 British airports exploited for the trade in "intelligence", most of it - says the Senate - worthless.

Mackay documented the horrific treatment of one individual now named by the committee. Direct British involvement was described. No-one resigned; no-one was arrested.

Nevertheless, the documentation has continued. In 2006, the SNP submitted a report to the Council of Europe proving - to any rational observer - the existence of the flights. Last year, researchers at the universities of Kent and Kingston, having built a database ­collating the movements of 120 aircraft, found conclusive evidence of traffic through Wick, Inverness and Aberdeen. It was enough to prompt Frank Mulholland, the Lord Advocate, to instruct Police Scotland to investigate.

At a guess, Cheney and the CIA might not be quaking at the thought. This is, in any case, the second attempt at an investigation. The first effort in 2007-08 failed to turn up evidence that was credible or reliable. But the US Senate has now denounced America's primary protective agency in terms that have shamed the country. Mulholland has told police, in effect, to take notice of the extraordinary fact.

In one sense, they could not do otherwise. Police Scotland have all the customary duties you might expect under international law in a country that calls itself civilised. But common law, Scots law, also imposes obligations. In theory - and I put it no higher - our pair of fictional Glasgow coppers are duty-bound to invite Cheney to answer a few questions involving possible crimes committed in their jurisdiction. Bluntly, we don't allow torture. So how would our American visitors and their masters explain themselves?

Judging by the philosophical ruminations of former vice-president Cheney on his favourite Fox News channel - it's all "crap", this torture stuff - they'd rather not. America has failed, conspicuously, to settle accounts for what was done in the Bush-Cheney years. There is plenty talk of indictments and arrests. No-one believes a word of it.

Britain, typically, has not even got that far. What became of David Miliband's flat denials that the UK "sanctioned" torture or was in any sense involved? What of Jack Straw's repeated assertions - sadly "untrue" - that our Government and its agents had no role? What did William Hague ever have to say, while Foreign Secretary, about the CIA's use of Diego Garcia in the Indian Ocean, a long-established British territory, as a "black site"?

As best, we know the UK's only interest has been in a considerable diplomatic effort to keep the country out of the Senate Intelligence Committee's document. In August, it was reported - thanks only to the Freedom of Information Act - that the ambassador to the US, Peter Westmacott, had met committee members on 11 occasions between 2012 and this year. What's that formula the spooks so cherish? "If you've done nothing wrong, you have nothing to fear"?

At the heart of the Senate committee's work is a finding that goes to the heart of the entire ugly argument over the global security state and the post-9/11 world. What has been achieved? How much "useful" intelligence was gouged from the bodies and minds of prisoners? Bluntly, how many lives were saved by countries discarding their democratic principles and spurning the rule of law?

The Senate Select Committee on intelligence is not composed of nature's radicals. Historically, it has only rarely failed to take the spooks at their word. The worth, purpose or decent intent of the CIA is never doubted. But in more than 500 pages - and that's just the summary - the committee portrays an agency that was inept, dishonest and wedded to disgusting methods that did not, in fact, work. The torture programme was horrible. It was also dumb.

Police Scotland should be encouraged to ask their questions, starting at home. They should be joined by police the world over. This might prove to ordinary citizens that reasonable questions are too often met by an unreasonable silence, that our safety has now become a permanent excuse for the state within the state.

The advocates of torture, like Cheney, have few justifications now. While democracy is debauched we are left with a just-in-case argument: systematic abuse merely to be on the safe side, to guard against a possibility while reality becomes still more dangerous than before. Yet, ironically (or comically), Britain has a bigger problem than the US. The behaviour of Bush and his crew was more or less known. Our Westminster politicians just lied, time and again.

Sending round a DI and a DC from Police Scotland might not be such a bad idea. If tortured prisoners were on our soil they are, in any sense that counts, on our consciences. Scots law has plenty yet to say about that kind of offence.