If you have been following the Prime Minister’s ongoing stand off with the Scottish National Party – and why wouldn’t you be? – you might have noticed a marked shift in how the Government is taking the fight to the separatists.

Rather than simply reciting the usual lines about “our precious Union” and the fact that the 2014 referendum was supposed to be “once in a generation”, Boris Johnson has been repeatedly attacking the Scottish Government’s record on bread-and-butter issues such as education and health.

This isn’t the first time the Tories have tried to put a spotlight on the poor performance of the devolved administrations. David Cameron went hard on Welsh Labour’s NHS record at the 2015 election, branding Offa’s Dyke “the line between life and death”. Michael Gove also tried to contrast Cardiff’s dire education performance with the Government’s school reform agenda.

But such efforts have previously been infrequent, whereas they now seem to be becoming a more central part of the anti-separatist strategy – a stealthily devo-sceptic note which is both overdue and welcome.

Unlike straightforward appeals to the Union, attacking the SNP’s record in government actually has the potential to reach middle-of-the-road voters who aren’t already convinced unionists. Johnson just won a landslide on the back of a promise to ‘get Brexit done’, and it makes sense for him to try to apply this get-on-with-the-day-job approach to the Scottish question too.

It also creates cover for the Government to start parking its tanks on the Scottish Government’s lawn. In recent years there has been a growing tendency for the devolved administrations to spend public money duplicating reserved functions – such as foreign affairs – whilst fighting tooth and nail against any perceived incursion by Westminster onto ‘their turf’. See for example the row over the badly-mislabelled “post-Brexit devolved powers“.

Yet now we read that the Prime Minister is mulling UK-level policies that at least impact on devolved competencies, such as this story about a new bursary to encourage students to study in different parts of the country and prevent the development of higher education silos via the ‘home tuition’ arrangements established by Edinburgh and Cardiff.

If the Government has the will, there is plenty of running to be made here. Since the advent of devolution in the late 1990s both Wales and Scotland have performed badly in key areas. The latest evidence bears this out again. Those responsible are not fond of this being pointed out: when Gove made his above-mentioned intervention a Welsh Labour minister accused him of harbouring “invincible colonial attitudes” towards the Principality.

But if we’re to stick with devolution, there is an obvious role for Westminster in preventing the devolved administrations from marking their own homework. One of the upsides of the system, in theory, is that it allows different policies to be tried and compared. Whitehall should be tasked with facilitating that comparison, even – indeed, especially – if this plan is met with outrage in Holyrood and Cardiff Bay.

Establishing a UK-wide set of metrics for assessing outcomes in areas such as health and education, and regularly publishing the figures, would be a good place to start. An even bolder development would be to formally enshrine Parliament as the ultimate guarantor of acceptable public services nationwide, with a remit to step in in the face of persistent failure at the devolved level.

All of this is potentially a serious break from the magical-thinking devolution strategy of the past two decades. But as I have written elsewhere, that is a very good thing.