Tom Peterkin: Nicola Sturgeon's attack on Kezia Dugdale may backfire

First Minister Nicola Sturgeon created a stir in Tuesday's live TV debate by revealing the details of a private conversation with Scottish Labour leader Kezia Dugdale.

After several long weeks of dreary political catchphrases, the 2017 General Election has finally sprung into life thanks to the hand grenade tossed by Nicola Sturgeon in the direction of Kezia Dugdale.

The SNP leader’s claim on live TV that Ms Dugdale had confided in her that she would not stand in the way of a second independence referendum was easily the most explosive moment of the campaign north of the border.

A sharp intake of breath greeted Ms Sturgeon’s “revelation” during the STV debate that the Scottish Labour leader wanted to drop Labour’s opposition to another independence poll following last year’s Brexit vote.

To disclose her version of a confidential conversation during such a high-profile event and so close to the opening of the polls had more than a touch of the Machiavelli about it. It was a manoeuvre that wouldn’t have looked out of place in the House of Cards play-book and finally injected a bit of drama into the torpor of the last few weeks.

Scottish voters go to polls as multiple seats up for grabs

As Ms Sturgeon was scolded by her opponents for betraying a confidence and “dragging politics into the gutter”, the question on many observers’ lips was: why had the First Minister resorted to this tactic?

Presumably Ms Sturgeon saw some political advantage in making the disclosure. But the widest grins in the “spin room” after Tuesday night’s debate had finished were being worn by the Tories. By deliberately undermining Ms Dugdale’s opposition to another independence referendum, Ms Sturgeon appeared to be playing into their hands.

With the election in Scotland being characterised as a constitutional battle between the SNP and Conservatives, Ms Sturgeon’s intervention would surely encourage No-voting Labour supporters to shift to Ruth Davidson’s party.

That sort of movement could prove crucial in seats like Moray and Perth and North Perthshire where the Conservatives are desperate to unseat the SNP big guns Angus Robertson and Pete Wishart.

This point was grasped in the heat of the debate by Ms Davidson, who deployed her excellent political instincts to capitalise on Ms Sturgeon’s claim. Turning to the SNP leader, Ms Davidson asked: “Did you just tell people you had a private conversation with Kez Dugdale last June where she said she was going to drop Labour’s opposition to independence?”

In contrast to the Tory leader, Ms Dugdale appeared caught off guard, failing to issue a categorical denial when given the chance to do so by debate chairman Bernard Ponsonby.

During the debate, Ms Dugdale restricted herself to saying that the idea that she would do anything other than protect the UK and fight to remain in the Union as “absolute nonsense”. The more fulsome denials from the Scottish Labour leader came after the credits had rolled.

By then Ms Sturgeon’s gambit was making the headlines and dominating discussion about the debate – not all of which appeared helpful to the SNP leader.

By bringing up her conversation with Ms Dugdale, Ms Sturgeon was not only helping the Conservatives but also allowed her critics to question her trustworthiness.

Ms Sturgeon must have calculated that there was some advantage to her by making public details of the conversation, which took place on mobile phones the day after the Brexit vote.

The Scottish election may be seen as a straight fight between the SNP and Tories north of the border, but perhaps the detonation of Sturgeon’s hand grenade suggests SNP intelligence has picked up a Labour threat under the radar.

Has the Corbyn effect filtered through to those seats in the West Coast which saw the SNP profit from disaffected Labour voters when Ed Miliband was running the show?

Or perhaps undermining Labour’s stance on the constitution stands to benefit the SNP in seats like East Lothian and Edinburgh South where pro-UK tactical voters see Labour candidates as the best chance of defeating the Nationalists.

A more prosaic explanation could be that Ms Sturgeon mentioned the Dugdale conversation in an attempt to distract from the criticism that she has been receiving over her domestic record.

Until Thursday night, every televised debate involving Ms Sturgeon had concentrated on declining standards in the classroom and problems in the National Health Service. When forced on to that ground, Ms Sturgeon has looked her most vulnerable.

The other matter that has proved damaging for Ms Sturgeon’s has, of course, been the issue which this spat was about.

With the opposition parties using every opportunity to speak out against indyref2, Ms Sturgeon has been a lone voice amongst the main leaders. By claiming that Ms Dugdale was in favour of a vote when they spoke last June, Ms Sturgeon is attempting to detoxify the issue.

Yesterday SNP sources were down-playing suggestions that Ms Sturgeon’s tactic was to call out Ms Dugdale’s “hypocrisy” on independence. Their argument was that Ms Dugdale was entitled to change her mind on the issue, but she shouldn’t base her election campaign on the idea that another vote is beyond the pale.

Whatever Ms Sturgeon’s motivation, one of the risks for the SNP is that voters judge that the episode does not reflect well on the First Minister’s integrity.