ON October 11, 2010, weeks into his prosecution for perjury, Tommy Sheridan sacked his defence team. Having already dispensed with the services of Donald Findlay, the former SSP MSP gave Maggie Scott QC her jotters.

Freed from his lawyers’ restraining influences, Sheridan conducted his own defence in characteristically rambunctious style.

He stood accused of committing a fraud on the court, lying in order to win £200,000 in damages from the now-defunct News of the World newspaper.

Against the backdrop of the gathering storm of the phone-hacking scandal, Sheridan promptly supplemented his witness list with a number of former News International employees, including the Prime Minister’s serving director of communications, Andy Coulson.

Placed under oath in court, the former News of the World editor found himself fending off questions about his relationship with convicted hacker Glenn Mulcaire, and his knowledge of the private investigator’s illegal practices.

This was a political spectacle of some drama. What was less obvious, however, was how any of this related to the Crown’s allegations that Sheridan had misled the civil courts about his private life in dishonest pursuit of a large defamation payout. This irrelevance came back to haunt the Crown yesterday, as Lord Burns acquitted Coulson on a no case to answer motion, concluding that “not every lie amounts to perjury” in Scots law.

This may seem like a strange proposition, but it isn’t new. In 1985, Lord Justice General Emslie held that a “charge of perjury will not lie unless the evidence alleged to be false was both competent and relevant at the earlier trial either in proof of the libel or in relation to the credibility of the witness.” Lying under oath isn’t enough. The lies have to be relevant to the central issues in the earlier trial.

As far back as 2012, a number of lawyers expressed doubts about whether Coulson’s evidence met either of these tests. It always looked tricky for the Crown to establish his testimony was directly relevant to the Sheridan prosecution, however honest or dishonest it may have been. Discharging the jury in the High Court of Justiciary yesterday, the judge vindicated this scepticism.

The Tory spinner could not speak to Tommy’s confessional SSP executive meetings. There is no evidence that Coulson frequented the former MSP’s Cupid’s loveshack in Greater Manchester. He could have no insight into the dalliances and affairs alleged. A great conspiracy was claimed, but never evidenced. Sheridan calling Coulson to the stand was essentially a smokescreen defence. But don’t take my word for it. In his closing speech, even Sheridan recognised that it was a political sideshow.

In 2010, he told the jury which convicted him that “the reason I risked my defence to cite the likes of Glenn Mulcaire and Andy Coulson to give evidence wasn’t because I thought they were going to help my defence, it was because I think I have a public service and a public duty to expose wrongdoing.”

Back in 2010, the Advocate Depute prosecuting Sheridan agreed: Coulson’s testimony was a red herring. As Murdo Macleod QC, for Coulson, asked Lord Burns: “How can the Crown say in 2010 this evidence doesn’t matter then turn around in 2015 and say it does?”

And how, for that matter, can Sheridan?

Coulson has since been convicted in England of conspiracy to hack phones. For a man who may have lied in a Scots court to go free sticks in the craw. But it isn’t corruption, or conspiracy, or cover-up. No special exception has been made for Coulson. Indeed, even had Coulson been convicted, Sheridan’s subsequent appeal would have failed for the same reasons Coulson’s prosecution foundered. He would have to persuade appeal court judges Coulson’s perjured evidence was “not merely relevant but also of such significance that it will be reasonable to conclude that the verdict of the jury, reached in ignorance of its existence, must be regarded as a miscarriage of justice.”

Even if he was lying through his teeth, Coulson’s evidence could never meet those tests.

Tommy is guilty of perjury, whether or not Coulson lied. Case closed.