But it’s true: from across the political spectrum, there is consensus.

The downside for Davidson is that what unifies politicians, opponents and allies, is the belief that she should step down as an MSP. It’s quite the development in the career of a woman once credited with detoxifying the Conservative Party in Scotland.

Davidson’s announcement, last week, that she has taken a lucrative role with lobbyists, Tulchan (a tasty 50 grand for 24 days’ work each year), has horrified former allies and delighted opponents who, quite legitimately, have gone on the attack.

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It is hard to disagree with the point made by Davidson’s critics that being, at once, both a legislator and an employee of a lobbying company is entirely incompatible.

Davidson and her new employers may insist that she will not be involved in lobbying, but that is not enough to remove the stench from this situation. The former Conservative leader will be using expertise gained while employed as an MSP to advise corporate clients about the political landscape and that, I think, represents an insurmountable conflict of interest.

Until recently, Davidson was regarded by many Scots as the Conservative it was okay to support. After years during which the party appeared to be fading into obsolescence, she revived its fortunes.

Under her leadership, the Tories overtook Labour in the polls to become the largest opposition party at Holyrood. Davidson’s personality – she’s likeable and liberal – and her smart positioning of her party, post the 2014 independence referendum, as the chief defenders of the Union combined to make hers a most surprising success story.

And she might have taken her party to greater successes if it hadn’t been for the arrival in Downing Street of Boris Johnson. Davidson, a Remain campaigner in the 2016 EU referendum, found herself completely at odds with a Prime Minister who’d led Leave to victory and wished to see Brexit delivered at any cost. This conflict, combined with a desire to spend more time with her partner and their baby son, led her to step down from the political frontline. She relinquished the leadership of her party and signalled that she was likely to step down as MSP for Edinburgh Central at the 2021 election.

There was considerable anguish in Scottish Tory ranks about this development. Under Davidson’s leadership, candidates who would once have had no chance of winning seats found that they could do just that. To be part of Team Ruth was to be a different kind of Tory.

But dismay about Davidson’s decision was not confined to Tory ranks. Pro-Union politicians in both Labour and the Liberal Democrats were sorry to see her go (not that they’d have admitted as much in public).

Those politicians, her rivals in parliament, saw her as a key figure – perhaps the single most important figure – in any future independence referendum campaign.

If the SNP was to have the opportunity to ask Scotland to vote again on the future of the UK, then Davidson’s involvement in the campaign would be crucial. Her announcement that, though she was stepping down from the Conservative leadership, she intended to play a part in any future referendum campaign, was well received by Labour and Lib Dem politicians.

They reckoned, in fact, that they were getting the best of both worlds. They’d have Davidson, with her strong pro-UK credentials and gift for connecting with voters, and they wouldn’t have to deal with the problem of her being a key figure in Johnson’s party. They would get Davidson the Unionist rather than Davidson the Tory.

Her decision to take a position with a lobbying company has done for that.

Davidson now appears exactly like the sort of Conservatives from whom she once represented a break.

Until a few days ago, if you had asked any pro-Union politician who might take on the leadership of the Better Together campaign in a future independence referendum, Davidson would have been top of the list.

Now? Well, now she would be seen as a liability rather than an asset.

By taking on this new job, Davidson doesn’t just represent the kind of Conservatism that the SNP benefits from attacking, she represents the sort of “establishment” from which the nationalists insist Scotland must break free.

If Davidson was to take on a central role in a future independence referendum, she would face endless questions about her motives. “Well of course you want to keep Scotland in the UK,” her opponents would taunt, “because you want to line your pockets.”

As one SNP campaigner put it to me a couple of days ago: “She has written all our attacks for us.”

Davidson’s decision to step away from front-line politics represents a loss to our national debate. She has been an important figure, not just for her party, but in other ways, too. Opponents have praised her for discussing her sexuality and encouraging others to stand up against homophobia. She has been a great champion for equality and a role model for young people struggling with their identities.

In politics, as in comedy, timing is everything. Had Davidson waited until she had left Holyrood before taking on her new job as an adviser to a lobbying company, her appointment would have been entirely unremarkable. By taking on the job now, she has seriously – I believe fatally – undermined her credibility.

Calls for Davidson to step down from Holyrood grow louder by the day. She should, I think, heed them.

While she remains both a legislator and an employee of a lobbying firm, she damages not only herself and her party, she also damages politics. She plays her part in fuelling the idea that politicians are only ever in it for themselves.

Every day that Ruth Davidson remains an MSP will only increase damage to her party, to politics, and to the UK.

Euan McColm: Every day Ruth Davidson remains an MSP will only increase damage to her party