NICOLA Sturgeon wasted no time flourishing her mandate for a second independence referendum in the wake of the SNP’s emphatic election win.

It has been “renewed, refreshed, and strengthened” she said. But has it?

The SNP’s manifesto was certainly straight-forward on the point.

“A vote for the SNP in this election is a vote to endorse the following proposition: it must be for the Scottish Parliament not Westminster to decide when an independence referendum should be held and the SNP intends that it will be in 2020.”

Launching the manifesto last month, the First Minister also said an SNP win would be a “clear instruction” to get on and hold the vote next year.

Her party’s gains on that basis, and the Scottish Tories’ losses on an equally direct “No to Indyref2” platform, suggest it ought to be cut and dried.

However, although the SNP undoubtedly has momentum on Indyref2, the existence of a mandate is not so simple, given Ms Sturgeon has built it on rickety foundations.

The language she used in the early hours of Friday morning was telling.

She did not say the election had generated a mandate from scratch.

Rather, she said it had "renewed, refreshed, and strengthened” a mandate that already existed, and that's the snag. 

The First Minister has consistently identified the 2016 Scottish election as the source of her mandate, arguing it has been raised to ever greater levels of awesomeness through successive elections and votes in Holyrood.

For a while, in response to Theresa May saying now was not the time for Indyref2, the First Minister said her mandate was “cast-iron”.

Then, in 2017, she said the SNP winning most Scottish seats would upgrade to a “triple-lock” version. This week’s win is the latest tier of the tower.

But it is all constructed on a muddled, mongrel mandate.

True, the SNP and Scottish Greens won a majority of Holyrood seats in 2016.

But their MSPs were elected on very different manifestos when it came to independence.

In the wake of the No vote just 18 months previously, both parties felt obliged to tiptoe round the issue.

To avoid being accused of ignoring the public’s will, they resorted to tortured formulations that have undermined the notion of a clear mandate ever since.

In the 2011 Scottish election, the SNP had been clear and upfront.

“We will give Scots the opportunity to decide our nation’s future in an independence referendum,” said the manifesto on which they won an absolute majority, triggering the referendum of 2014.

But in 2016, that straightforward pitch was rewritten and made contingent on other events.

The manifesto position became a statement that Holyrood “should have the right to hold another referendum if there is clear and sustained evidence that independence has become the preferred option of a majority of the Scottish people - or if there is a significant and material change in the circumstances that prevailed in 2014, such as Scotland being taken out of the EU against our will.”

Despite Ms Sturgeon’s subsequent elevation of it, at the time this was essentially a box-ticking exercise. Like most of the country, the SNP did not believe Brexit would happen. It famously spent less money campaigning to stay in the EU than it did on a byelection in Glenrothes.

However, as the main party of independence, it had to refer to a referendum somehow.

So it arrived at a baroque, Brexit-related form of words that held out the possibility of independence, albeit in what it then considered highly improbable circumstances.

The SNP then went backwards in 2016. Although its constituency vote share rose 1.1%, their regional share fell 2.5%, and they fell from 69 MSPs to 63, losing their overall majority.

A rum sort of basis for a mandate.

Meanwhile, the Scottish Greens went off on their own tangent.

Their 2011 manifesto had touted “a multi-option referendum with choices including the status quo, a stronger Scottish Parliament with powers defined through a participative process, and full independence based on a written constitution”.

But by September 2015, the Greens said the timing of Indyref2, should no longer be the plaything of politicians.

Instead it “should be determined by public appetite… For example, a call for a referendum signed by up to 1m people on the electoral register”.

Thus their 2016 manifesto said: “If a new referendum is to happen, it should come about by the will of the people, and not be driven by calculations of party political advantage. In such a referendum the Scottish Greens will campaign for independence.”

But there was never a petition.

All of which gives Boris Johnson enough room to contest the validity of Ms Sturgeon’s mandate, at least until the 2021 election comes round. At which point she may well win a mandate that cannot be gainsaid.