NICOLA Sturgeon is to launch the SNP’s long-awaited "summer initiative" on independence with a hard-nosed look at where the Yes side must improve to win next time.

The First Minister will start the "national conversation" in Stirling this week, at an away-day with her MSPs, MPs and MEPs.

The move delivers a pledge Sturgeon made in her speech to the SNP conference in March.

Describing the need to convince No voters to switch sides, she said: “This summer the SNP will embark on a new initiative to build support for independence.

“We will listen to what you have to say. We will hear your concerns and address your questions - and in the process, we will be prepared to challenge some of our own answers.”

The initiative was delayed after the Brexit vote in June, but will now be launched on Friday, just before Holyrood returns from summer recess.

Opposition MSPs urged Sturgeon to axe the plan and focus on “bread and butter issues”.

A source close to the First Minister said: “It’s going to be about engaging with the public and taking their views. It will be a listening exercise.

“It’s the first stage in gathering people’s views of independence, what works for them and what doesn’t, the benefits and the perceived difficulties.”

The source said the initiative would look at how spending priorities could change after independence using future North Sea oil revenue and money saved from scrapping Trident.

However it would also consider the tougher questions facing the Yes movement, including the perceived weaknesses in 2014 around the currency, economic growth and the deficit.

Last week, the Scottish Government’s own GERS figures showed public spending in Scotland was £14.8bn more than was raised in tax in 2015-16 because of the oil price collapse.

The deficit, equivalent to 9.5 per cent of Scottish GDP, was higher even than Greece's 7.2 per cent deficit.

Sturgeon insisted the Scottish economy remained on firm foundations and GERS did not represent the “day one” of a future independent Scotland, as that would depend on a host of financial negotiations with the rest of the UK.

The initiative is also expected to include an appeal to experts and academics to become involved with shaping the debate on independence as part of a broad ‘Team Scotland’. The exercise will be “public facing” rather than directed at SNP members.

Unlike previous “national conversations” designed to shift opinion before the last referendum, the current initiative will be paid for from party funds, not the public purse.

The source added: “We have to update the case for independence of 2014, most obviously because of Brexit.

“We can’t just dust off the last White Paper. If there is to be a second referendum, we need to build the case for it.”

The 'initiative' idea was only inserted in Sturgeon’s speech the night before she gave it at the suggestion of her special adviser Noel Dolan as an “applause point”, and the SNP leadership did not anticipate the ecstatic response it received.

Party insiders also admit that, before Brexit, the exercise was intended to occupy the SNP’s 115,000 members, as there seemed no chance of indyref2 for at least five years.

However, Brexit changed that, suddenly making another referendum “highly likely” according to Sturgeon, and so the summer initiative has taken on a far greater significance.

Scottish Tory leader Ruth Davidson urged Sturgeon to scrap the “unwanted” scheme and accused her of breaking a pledge not to pursue indyref2 without an upturn in public support.

“The SNP has a choice – to be Scotland’s builders or Scotland’s wreckers. To look to the future, or to take us back to the battles of the past. It is high time we had a Scottish Government that acted for all of us, not just its own narrow interests.”

A Scottish Labour spokesman said: “With so many challenges facing Scotland - the attainment gap in classrooms, the huge deficit exposed by GERS, lack of access to affordable childcare and the link between poverty and ill-health - it's time for the SNP Government to focus on the bread and butter issues."

Scottish LibDem leader Willie Rennie said: "The SNP and Tories have identical, super-sized wrecking balls. The Tories wrecked our place in Europe and the SNP want to wreck our place in the UK. Liberal Democrats are the only party committed to our place in the UK and Europe."

The SNP initiative is the latest in a series of recent Yes campaign revivals. The Scottish Independence Convention announced last week it was “getting the band back together” with a social meeting in Glasgow on September 18, followed by a more formal conference in January.

A grassroots Yes Movement rally is also planned at Glasgow Green on the second anniversary of the referendum, and the Radical Independence Campaign is about to hold a series of assemblies.

Convention supporter and SNP MP Tommy Sheppard said: “The name of the game is dialogue. We need to have a big conversation in this country and the people who voted Yes have to talk to the people who voted No and find out what they think are the constitutional options for this country.

"June 23 changed things. Things are not as they were. We can now engage with layers of opinion in Scotland we thought had maybe been closed off.”