NICOLA Sturgeon has pledged to reignite the independence debate this week with the publication of a new blueprint outlining how Scotland can go it alone – as critics accused her of pursuing separation "at any cost".

The First Minister said the country had the chance to focus “very much on ambition and hope” in the wake of the despair many felt around Brexit.

But Scottish Labour leader Richard Leonard insisted: “Scotland does not need, and the people of Scotland do not want, this tired argument again."

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Ms Sturgeon's comments came as the SNP prepares to unveil a long-awaited document looking at the economy of an independent Scotland, which is expected to support the creation of a new currency.

The Growth Commission, chaired by former SNP MSP Andrew Wilson, was set up in 2016 to "explore options to grow Scotland's economy in the wake of the EU referendum and consider how to generate further growth with the powers of independence".

Meanwhile, Scottish Conservative leader Ruth Davidson warned the UK needed to become less London-centric to strengthen and protect a union that "remains under threat".

She urged action as a new poll found support for the union at its weakest in Scotland, at just 52 per cent, compared with 68 per cent in England, 66 per cent in Wales and 59 per cent in Northern Ireland.

Delta Poll surveyed around 500 people in each of the four nations of the UK on behalf of the centre-right think-tank Policy Exchange. The majority thought Brexit had made the break-up of Britain more likely.

Ms Sturgeon told ITV she would consider the timing of a new independence referendum once there was clarity over the UK’s withdrawal from the EU, “hopefully” in the autumn.

She said: "I'm not going to say more about that in advance of that moment arising.

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"But of course over the next couple of weeks we will, I suppose, restart a debate about why independence for Scotland is an opportunity and what those opportunities are.

"As you know we've had a Growth Commission looking at the economic opportunities of independence.

"Its report will be published in the coming days and I think that's quite an important moment, because if you think about the last couple of years in the UK it has been very much a debate about how we cope with the damage of Brexit.

"What I think Scotland now has the opportunity to do is look at how we seize the opportunities that lie ahead, so a debate based very much on ambition and hope not a debate that's based on despair, which is how the Brexit debate so often feels."

Ms Sturgeon also repeated her assertion that the SNP would not block a second Brexit referendum on the terms of any deal with the EU.

The SNP’s 400-page Growth Commission, which is due to be published on Friday, will make recommendations on the monetary policy for an independent Scotland as well as laying out other costs and benefits.

Reports indicate it will support a gradual transition on currency, with Scotland continuing to use the pound before switching to a new currency which would initially be pegged to Sterling.

“Golden visas”, which would give people from outside the country the right to live in Scotland if they agreed to invest a certain amount in the economy, are also expected to be floated.

Critics said the currency plans were a “recipe for instability” and “wholly unworkable”.

Ahead of a speech on the union at the Policy Exchange in London today, Ms Davidson said it was “unlikely” the SNP’s latest drive would be met with enthusiasm, but warned against complacency.

She called for major institutions – such as the British Museum – to consider setting up elsewhere in the UK, as well as for most fishing infrastructure to be moved to Scotland. More government posts should also be spread around other parts of the country, she suggested.

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She added: "With Brexit, we have an opportunity to ensure the powers that return to these shores are based nearer the communities they serve.”

Ms Davidson insisted it was "not an anti-London argument", adding: "Indeed it was London which showed how we come together as a nation during the Olympics in 2012.

"The huge success of that event was that it allowed Britons to feel they had a stake in their country; that this event was ours.

"That should be our goal so people, including those who currently support independence in Scotland, feel the UK is theirs too.”