NOW is not the time, Theresa May claims, to hold a second referendum on Scottish independence. By “now”, she means the spring of 2019 at the earliest.

By talking in terms of timing, Mrs May has conceded she may not be able to prevent one. Fellow Tories Ruth Davidson and David Mundell yesterday seemed to argue the opposite. But their position is untenable – unless they deny Holyrood’s democratic validity.

Given the SNP’s dominance of the Scottish political landscape it is difficult to dispute Nicola Sturgeon’s mandate for her actions. The manifesto the SNP were elected upon was unambiguous in reserving the right to call a referendum in the event of material change of circumstance (with Brexit against the will of the Scottish people being the very example used for this, during campaigning).

In claiming there is no public or political consent for a second independence referendum, Ms Davidson appears to be attempting to contrast the “mood of the country” with the policies of those it elects.

But when MSPs likely back another vote on Wednesday, she will find herself effectively arguing against the legitimacy of the parliament she herself sits in.

This plays into Ms Sturgeon’s hands. Her camp calls Mrs May’s position an “epic mistake”, characterising the prime minister as afraid of Scottish voters. There is still a sense Mrs May is being outmanoeuvred by the SNP.

Yet the Prime Minister may be right that a vote should not be held until the Brexit process is complete. In many ways this is reasonable and could find favour with the Scottish electorate. Being asked to decide on independence, as a result of Brexit, without knowing the outcome of that process, is counterintuitive.

Ms Sturgeon may also find it very difficult to win an independence vote unless the public know exactly what is on the table, post-Brexit. A lack of hard facts about issues affecting the economy and currency was among the factors which led to a No vote in 2014. Indeed, the first minister allowed for the possibility of a later vote open when she said on Monday Scotland might indicate it wanted a different relationship with Europe before an EU exit “or within a short time after it”.

The lack of clarity about the UK Government’s intentions was only underlined by David Davis’s extraordinarily inept, performance before Westminster’s Brexit committee this week. An outline deal has been promised before the end of next year. Even without one, many voters will have already made up their minds either way.

This is really a political chess game. The Prime Minister knows it would be potentially disastrous to refuse a referendum outright, so is reduced to haggling over the timing, while attempting to put pressure back on the SNP.

But Holyrood backing for a referendum next week would only confirm her limited options. Mrs May, and her party colleagues in Scotland, are understandably keen to respond robustly to the SNP’s attempts to secure a second referendum. But their statements have demonstrated little but the relative weakness of their position.