Scotland's First Minister Nicola Sturgeon has announced her plans to hold an independence referendum in a scathing speech attacking the British government's handling of the process to leave the European Union.

Sturgeon has instructed the Scottish Parliament, where her Scottish National Party (SNP) is the largest party, to authorise a referendum and to request a section 30 order from the UK government, which would allow it to take place.

Scotland’s parliament, based in Edinburgh, has the power to legislate on a number of issues including taxation, education, and health policies, but the UK reserves the power to allow an independence vote to take place.

The SNP’s 63 members of the Scottish Parliament fall just shy of a majority, but the pro-Independence Green party would make up the numbers needed for a vote to pass.

Last month, members of the Scottish parliament voted 90 to 34 against triggering Brexit, but the move was symbolic as the Supreme Court had already ruled that the British government only needed consent from British politicians sitting in Westminster.

Scotland rejected independence before in a referendum in 2014 when 55 percent of the population chose to remain apart from the UK.

But that was before the UK voted last year to leave the EU, a decision 62 percent of Scots voted against.

Scottish nationalists maintained that a second referendum was a possibility given "significant and material change in the circumstances that prevailed in 2014", which Sturgeon maintains is exactly what Brexit will bring.

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British Prime Minister Theresa May has repeatedly stated her objections to permitting a second Scottish independence vote.

Commenting after Sturgeon's speech, a Downing Street spokesperson said the move would cause “huge economic uncertainty at the worst possible time”. May later condemned the SNP's "tunnel vision".

If May allows the referendum to go ahead, she would have to campaign to keep Scotland a part of the union as she simultaneously negotiates a complex divorce with the EU.

If she refuses, she would incur anger from the Scottish public that would turn many on the fence towards the nationalist cause.

'No compromise'

Even leading unionist and Scottish Conservative leader Ruth Davidson has warned Westminster against blocking a second independence vote.

In her speech on Monday, Sturgeon painted a picture of an unequal partnership in which London and not the Scottish people decided the fate of their country.

“The UK government has not moved even an inch in pursuit of compromise and agreement,” the SNP leader said

“The language of partnership has gone completely,” she added.

Attempts to stop a second vote would help to reinforce that idea.

The UK government has not moved even an inch in pursuit of compromise and agreement Nicola Sturgeon, Scottish First Minister

However, a successful vote for independence is nowhere near a certainty for Sturgeon and polls show Scottish support for leaving the UK teetering at 50 percent or just below.

Support for the EU was strong in Scotland but far from universal, including in her own party with 36 percent of SNP supporters voting to leave the EU.

Sturgeon was careful in her language; her criticisms of the UK government centred on its decision to leave the single market rather than the EU itself.

The 2014 vote was billed as a “once-in-a-generation” vote, but amid the ruptures of Brexit, and a government in London struggling to deal with the scale of negotiations with the EU, there may not be as good an opportunity for today’s nationalists to push for independence.