The Scottish Government has warned Theresa May that blocking a second independence referendum would be an "epic" miscalculation. 

A spokesman for Nicola Sturgeon described the Prime Minister's statement that now was not the time for another vote as "vague". 

He added that if the implication was that Mrs May proposed to veto a referendum then “that would be completely and utterly democratically unacceptable”. 

“This is a 21st century democracy where elections, mandates and votes are meant to count for something”. 

Rejecting a vote “would play disastrously and be a miscalculation of epic and historic proportions”, he added. 

In her speech on Monday Ms Sturgeon suggested that a referendum should be held between autumn 2018 and spring 2019. 

But her spokesman said that another vote could be held as late as May 2021, the end of the current Scottish Parliament term. 

Ms Sturgeon herself also said that to veto a vote would be “undemocratic” and “proof positive that the Tories fear the verdict of the Scottish people”.

Earlier, Theresa May has ruled out another independence referendum before Brexit.

The Prime Minister made the announcement less than a day before the SNP's conference opens in Aberdeen.

In an interview with ITV, she said: " Now is not the time."

She added that it would be "unfair to the people of Scotland who would be asked to make a crucial decision, without the information to make that decision".

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ITV's Robert Peston added that Mrs May had told him that she would not approve another referendum.

She said that with the UK facing exit talks with the European Union that: "Right now we should be working together not pulling apart”.

Mrs May added: “I say to the SNP: now is not the time”.

The Herald revealed earlier this month that Downing Street believed a second referendum before Brexit negotiations end would not be "fair".

Before the 2014 referendum both the Edinburgh and London governments agreed it had to be "fair, legal and decisive".

Mrs May has previously accused the SNP of "game-playing" over the constitution and urged the party to concentrate on issues like education.

But blocking another referendum for at least two years will open the Prime Minister to the charge that she is ensuring

Earlier this week, David Mundell told The Herald: "It would be impossible for people in the timescale suggested by Nicola Sturgeon to make a reasoned view and, therefore, have a legal, fair and decisive referendum as we did in 2014 on the basis of the facts as they would be aware of them at that point.

"If you are saying you want the referendum because of Brexit, then you have to know what the arrangement is that the UK has secured in relation to leaving the EU and how that has been delivered and, of course, you need to know what the SNP alternative to that proposal is," added Mr Mundell.

At First Minister’s Questions earlier, Scottish Conservative leader Ruth Davidson said her party would reject the proposals set out by the SNP on Monday.

She said: “The Scottish Conservatives reject the proposals set out by the First Minister on Monday.

“A referendum cannot happen when the people of Scotland have not been given the opportunity to see how our new relationship with the European Union is working.

“And it should not take place when there is no clear political or public consent for it to happen.

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“Our country does not want to go back to the divisions and uncertainty of the last few years.

“Another referendum campaign will not solve the challenges this country will face.

“We don’t want it. We don’t need it.”