In the distant past of a few weeks ago, observers of the Conservative campaign were talking about how the sheer inevitability of Theresa May’s landslide might lead to complacency amongst Tory voters.

CCHQ seem to have set rather too enthusiastically about solving that particular problem. As I wrote a new poll from Ipsos MORI, one of the pollsters showing much better Tory results, has found the Conservative lead slashed from 15 points to five. Labour are on 40 per cent.

Is Jeremy Corbyn going to get 40 per cent? By the standards of recent decades it would be unimaginable, but at the minute it looks like the Tories are having an OK election in a contest with 1970s levels of support for both the main parties.

Regardless, if there is a silver lining to the dark storm clouds looming over Number Ten, it’s that the tactics the Party honed in 2015 to combat an apparently-viable Labour Party are, well, worth deploying again. On the subject of which: talk of pacts between Labour and the Scottish Nationalists are back in the headlines.

According to the Daily Mail and the Times (£), Corbyn has revealed how he intends to handle forming a government in the event that Labour is in a position to form a minority administration. He’s basically going to call the Nationalists’ bluff. As Emily Thornberry puts it:

“If we end up in a position where we are in a minority, we will go ahead and we will put forward a Queen’s speech and a budget, and if people want to vote for it then good. If they don’t want to vote for it, they are going to have to go back and speak to their constituents and explain to them why it is we have a Tory government instead. If we are the largest party we go ahead, no deals, with our manifesto, with our budget and our Queen’s speech, and that’s the conversations we have had, that’s it, no deals.”

Nicola Sturgeon’s, likely somewhat dimished, phalanx of MPs would have the option either of endorsing Labour’s proposals without extracting concessions or abstaining and allowing Conservative and Northern Irish unionist MPs to bring Labour down. In the still-unlikely event that the SNP were confronted with this scenario, they would be in a genuine bind.

Extorting constitutional concessions and sundry pork is the job of regional parties which can’t form a government. Impotence in the face of a Conservative majority is one thing, but in the event of a hung parliament the spotlight would be back on the Nationalists in a big way and they couldn’t afford to roll over.

On the other hand, if Corbyn were to stick to his guns (and not concede a second independence referendum, which he’s said he has no great objection to) they’d likely be very wary of reprising their role from 1979 and allowing the Unionist parties to oust a more sympathetic administration. A Tory government in London may be good for the SNP, but not if Labour can reasonably argue that they put it there.

As a campaigning tool, the prospect of a Lab-Nat pact may be blunter than 2015. Then Ed Miliband had been consistently viewed as a competitive challenger for a long time, unlike Corbyn, and the Nationalists seemed more prominent and potent only months after the 2014 Scottish independence referendum.

Nonetheless, it could hurt Labour in some of the northern, working-class seats where Brexit is the defining factor of the election, given that Sturgeon and plausibly be presented as a major drag on any Labour administration’s commitment to upholding the referendum result and taking us out of the EU.

It may also help to corral unionist voters behind the Tories in Scotland, where a recent poll showed Labour regaining ground (one put them and the Tories on 25 per cent apiece). The distribution of votes means only the Conservatives are likely to make substantial gains, but Ruth Davidson will be hoping for another strong second place and anything which undermines Labour’s credibility on the Union will help.

Tory strategists have got their wish: the “coalition of chaos” is now, according to the polls, a credible threat. Now we shall see how effectively they can deploy this line of attack, and how persuasive it is.