ALL Holyrood is in a tizz. Peter Murrell, Nicola Sturgeon’s lesser-spotted husband, is about to come blinking into the spotlight next week.

Mr Murrell, the SNP’s chief executive for nigh on two decades, has been called to give evidence to the inquiry into the Alex Salmond affair.

For journalists and other sadists it will be an exquisite moment. It is not often the manager of a political party is quizzed by his rivals.

Affable but inscrutable, Mr Murrell hasn’t been thrust this hard into the media glare since he tied the knot with Ms Sturgeon in 2010, then swiftly burrowed back into the shadows.

But whatever nuggets MSPs extract from him on Tuesday, I suspect none will be as entertaining as his written evidence, parts of which are a hoot.

For Mr Murrell has kindly supplied the inquiry with the SNP’s various codes of conduct.

Read against the events of recent days, they glint with comedy gold.

Like the instruction that no member “shall abuse, harass or bully or maliciously defame any other member whether via the media or otherwise”.

Or the one just for MPs and MSPs which says no member of the parliamentary group “shall within, or outwith the Parliament, publicly criticise a group decision, policy or another member of the group”.

The latter was created on the eve of the 2015 general election to keep the newbies in line. How times change.

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The codes remain, the conduct is off the rails. Indiscipline seems endemic.

Last weekend’s conference - with slates of grassroots candidates ousting leadership favourites in internal elections - was bookended by extraordinary public bickering.

As a curtain-raiser, MP Joanna Cherry QC had a pop at the “cult” of Nicola Sturgeon and the mistake of putting “all your faith in one person”.

As for the hierarchy’s suppression of all things interesting at conference, “this no debate mentality is really unhealthy,” Ms Cherry told the Times.

Meanwhile fellow MP Alyn Smith attacked the SNP Common Weal group for running candidates, including Ms Cherry, who wanted greater internal democracy.

“Factionalism,” he fumed, shortly before being ousted as policy chief on the SNP’s ruling body while Ms Cherry was elected onto it.

Losing graciously is not on Mr Smith’s CV. Suggesting Ms Cherry should face disciplinary action by the party, he growled in a newspaper column about the “grave long-term consequences” from open dissent.

The feuding also lit up social media, where Ms Cherry had a second ding-dong with SNP MP Kirsty Blackman, and accused other folk of defamation.

The party’s justice spokeswoman is undeniably smart and effective, but you begin to suspect Ms Cherry could start a fight with a Quaker in a coma.

Finance Secretary Kate Forbes recently told the Politico website that reports of SNP disunity were exaggerated and “debate is good”.

But this is not debate. It’s a public slanging match. Less Oxford Union, more brawl in a pub car park.

In one way, it’s a coming of age.

A small party locked in opposition for decades, the SNP only became a party of power 13 years ago, and a mass membership party six years ago.

Discipline was simpler with smaller numbers and narrower aims.

But governing means engaging in a plethora of policy areas, while success attracts the sharp-elbowed and ambitious, so disagreement and backbiting have naturally come too.

Nor are internal groups unsual.

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After the success of the pro-Brexit European Research Group, the Tory party now has the Northern Research Group, the Covid Recovery Group and the China Research Group, from which MPs harry the Government over issues dear to their hearts.

However, while the various Tory groups seek results, the SNP has a personality-driven stramash.

That may change, of course, as the SNP groups settle down and try to effect change, but it’s not guaranteed.

The tangle of issues driving these spats - a Plan B on independence, women’s rights, trans rights, and whether to rehabilitate or repudiate Mr Salmond - are not easily resolved.

This is especially true if a party feels itself not simply more in touch with voters, more industrious, or more economically savvy than its rivals, but morally superior to them.

If you reckon you’re a better person than all your opponents, it’s hard to cede that high ground in search of a comprise. It would be moral slippage.

So for now the impression is a poor one. Worse, those haranguing one another online and in print appear to be unaware or unconcerned about how they look to the electorate.

Such blithe disorder is the flipside of success. Why bother behaving if you think the Holyrood election is in the bag? The party will still romp home, so a little aggro doesn’t matter.

If that rot has set in, I doubt it will make too much difference in May.

The public has bigger things on its mind. But it will notice in the end, and start to wonder if a party that can’t keep its own house in order can be trusted with the rebirth of a nation.

More immediately, if Boris Johnson keeps blocking Indyref2 after the 2021 election, the new indiscipline habit will see an explosive backlash to Ms Sturgeon’s failed softly-softly strategy.

Mr Murrell’s dud codes of conduct won’t save either of them then.