ON the face of it, it might seem like a curious policy offer to make the party faithful. As Liz Truss and Rishi Sunak descended on Perth last week to make their leadership pitches to the Scottish party, Rishi’s big idea was that the Scottish Government should be “properly scrutinised by the UK Parliament”.

Rather than putting his faith in the ­debating skills and penetrating political analysis of Douglas Ross and his colleagues in Holyrood, under Sunak’s scheme, the Scottish Government will be “required to publish consistent data on the delivery of public services so performance and value for money can be assessed against other parts of the UK”.

The idea any Scottish public services might outperform their UK counterparts – and so embarrass the London government rather than show up Edinburgh – ­apparently hasn’t occurred to the former-chancellor or his supporters in the party room. It is taken as axiomatic that ­everything is worse north of the border.

Under Sunak’s leadership, Scottish ­Government civil servants can also ­expect to receive summons from Westminster committees to justify their activities.

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Tory MPs can ask them ­whether they’ve ­spotted anyone who routinely vilifies the UK in St Andrew’s House. Prevent will be busy.

Truss, by contrast, offered the ­Scottish ­activist base a different commitment. Her plan is to reopen the Scotland Act “to ­reinforce the powers of the Scottish ­Parliament, correcting the fundamental power imbalance between the executive and the legislature in Scotland”.

She intends to do this by extending Westminster-style parliamentary privilege to MSPs “to ensure elected ­representatives hold the devolved administration to ­account for its failure to deliver the ­quality public services, particularly health and education, that Scottish people deserve”. To this extent at least, she’s harping on the same string as Sunak.

At first glance, this might also seem like a strange flagship pledge for Truss to make to stir Scottish Tory passions. But with a little reflection, the proposal speaks on an ­emotional level to the party’s ­persecution fantasies. You know the kind of thing. That we live in a one-party state. That the SNP-led administration – with its fearsome majority of five – exercises total and ­sinister control over Scottish public life.

If you chug this kind of Tory ­Kool-Aid, it isn’t the sustained failure of the ­opposition which keeps the SNP in ­office – but the friendly media environment and deferential and compliant ­broadcasters who fail to hold the Nationalists ­adequately to account. I can only assume they listen, read and watch different news sources to you and me.

The suggestion that Holyrood needs to look more like Westminster when it comes to parliamentary privilege isn’t original. It is a proposal which has gained traction inside and outside elected ­politics. Keir Starmer has spoken out in favour, as have some academics.

Bracketing the fever dream which ­inspired Truss’s intervention, I do think there’s a good case for taking a ­careful look at how we do this in Scotland. But parliamentary privileges have been ­devolved since 2016. Holyrood – not Westminster – should revisit the issue.

First, a bit of history. ­Parliamentary privilege has its ­origins in the 17th ­century – with the deposition of King James the VII and II and the ­installation of William and Mary. In England, MPs passed the Bill of Rights. Article 9 states that “the freedom of speech and debates or proceedings in Parliament ought not to be impeached or questioned in any court or place out of Parliament”.

In Scotland, representatives in the old Parliament of Scotland pressed the Claim of Right against the new sovereigns: “For redress of all grievances, and for the amending, strengthening, and ­preserving of the laws,” the Claim demanded, ­“Parliament ought to be ­frequently called and allowed to sit, and the ­freedom of speech and debate secured to the ­members”.

In practice, the more robust ­English text has tended to condition ­understandings of the scope of parliamentary ­privilege. In modern terms, privilege is ­understood to have two key aspects to it. First, it means Westminster enjoys “exclusive ­cognisance” over how its two Houses work – which is to say that peers and ­parliamentarians have the right “to ­organise their own affairs without ­interference” from outsiders – including the courts.

The second main dimension to ­privilege is freedom of speech and ­freedom of ­debate. In essence, this means ­anything said in parliamentary sessions or ­published by the parliament can’t give rise to any civil action, ground a criminal prosecution, or be held up as a contempt of court. This rule applies to MPs and peers – but also to witnesses participating in parliamentary work.

On the civil front, this means you can’t be sued for libel for the evidence you give to a parliamentary committee, or be pursued through the courts for damages for breaching a confidence. In criminal terms, it means MPs reading out material covered by the Official Secrets Act – or politicians making speeches intended to stir up racial hatred – can’t be charged with any crime. Reporting restrictions and contempt of court rules can also be ignored without legal consequences.

So where do things stand in Holyrood? It’s true, the language of parliamentary privilege isn’t used in the Scotland Act. ­Instead, there are a ­motley collection of “legal issues” which are ­intended to ­protect the integrity of ­parliamentary ­debate and proceedings. These are ­already considerably more ­robust than Truss ­implies.

And critically, they’re mainly aimed at external actors who might try to shut down the work of the parliament, rather than the executive. In modern times, the chances of a politician being detained by a squadron of halberdiers sent by the Queen to escort them to the Tower is ­vanishingly small. But the chances of an outspoken MSP being slapped with a defamation writ if they criticise a wealthy but misbehaving corporation? Now, that’s a different story.

Holyrood currently benefits from three levels of protection. First, the Scotland Act restricts the remedies which can be ordered against the devolved parliaments in civil cases. Second, it extends absolute privilege to parliamentary proceedings for the purposes of the law of defamation. If an MSP or witness makes a defamatory allegation at FMQs or before a ­committee – no libel case can be taken against them, even if the underlying claim is false. ­Lastly, there’s currently some ­qualified protection from contempt of court when MSPs are discussing a ­substantive ­legislative proposal.

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BUT beyond that? The ordinary civil and criminal rules that apply to you and me also apply to MSPs in the course of their work. They have to obey court orders, or face the consequences. Unlike MPs and peers, they can’t unilaterally exempt themselves from restrictions everyone else is subject to.

Recent experience has certainly thrown up some anomalies which could do with fixing. According to Holyrood, while absolute privilege extends to things ­witnesses say to parliamentary ­committees, it doesn’t apply to written evidence ­submitted and published by witnesses on the Parliament’s website. This seems an entirely artificial distinction which MSPs would be wise to do away with.

Holyrood also doesn’t have exclusive cognisance over its proceedings. Almost 20 years ago, the courts confirmed it was possible in principle to interdict an MSP from lodging a bill in the Scottish Parliament, meaning there is the real potential for parliamentary work to be interrupted by court proceedings in a way which seems difficult to justify in democratic terms. The rules on contempt of court could do with a fresh look.

But should an individual MSP be entitled to ignore a court order, or the general criminal law, in parliamentary debate? On this, the assumption that ­Westminster style parliamentary privilege is a good thing merits more anxious scrutiny. ­Parliamentary privilege can protect the free exchange of ideas, but as one recent Westminster report put it, it can also be a way of providing “inappropriate immunity for parliamentarians from criminal prosecution” in a way which isn’t obviously consistent with “the principle of fair and equal treatment in law.”