ONE of Nicola Sturgeon’s closest advisers has said she should offer the “softest possible” form of Scottish independence in order to win support from voters.

Andrew Wilson, who chaired the SNP’s Growth Commission, also likened leaving the UK to a “process rather than an event” and said Scotland was on a “journey without end”.

He said: “In the parlance of Brexit, we offer the softest of possible changes to the current arrangements, not the hardest. We recognise the level of integration and all the ties that have bound us for centuries. We create a platform that can unify a majority for progress that stands a chance of winning and winning big.”

And he mocked Yes campaigners who saw independence as an abrupt radical change.

“Some (a very small number) would rather move immediately and overnight to a Marxist revolutionary state. That is their right, but they won’t win the chance to try,” he said.

READ MORE: Former SNP MP's Indyref Tube plan branded 'unhinged'

The comments will infuriate many within the wider Yes movement and reinforce the impression of the SNP hierarchy deliberating deflating expectations over Indyref2.

SNP MP Angus Macneil, former MP George Kerevan and former SNP leader Alex Salmond have all argued using the chaos over Brexit to press for a second referendum.

But in an America TV interview last week, Ms Sturgeon said it was too soon for voters to come to an “informed decision” and “calm consideration” was required instead.

READ MORE: Nicola Sturgeon: too soon to make 'informed decision' on independence

Mr Wilson, a former MSP who is now a corporate lobbyist, last year produced the SNP’s updated economic blueprint for an independent Scotland.

It argued for a decade of restrained public spending after a Yes vote in order to halve Scotland’s deficit, and the unofficial use of sterling instead of a new Scottish currency.

His Growth Commission is now being chewed over by the SNP members.

Writing in The National, Mr Wilson said Brexit meant there had been a fundamental change in circumstances since 2014, and the last White Paper on independence.

Brexit had also shown how long and difficult constitutional change could be.

READ MORE: SNP MP warns against 'bouncing' country into Indyref2

He wrote: “The reality is that all change of such significance in any organisation, let alone a major country, is a process rather than an event.

“Transitions take time as issues are worked through, new institutions built, agreements struck, and strategies put into place and then into action.

“A new Scottish White Paper will require to learn many lessons from 2014, what has happened since and what is going so comprehensively wrong with Brexit.

“The report of the Sustainable Growth Commission was designed to answer a brief to think through all of these points. It does not shirk the difficult questions and seeks to provide a sound framework and straight and honest answers. In doing so it seeks a prospectus that can unify a settled will behind Scotland’s next step along our ‘journey without end’.”

READ MORE: Alex Salmond takes swipe at SNP leadership over Indyref2

Mr Wilson said “all of would love Rome to be built in a day”, but the lesson of Brexit was that “honesty, candour and realistic vision” was the most likely to succeed.

On currency, he said an independent Scotland would start bny keeping the pound, and only move to its own currency and Central Bank if six key economic tests were passed.

“This question could be re-examined every year in a report to Parliament,” he said.

In simple terms, passing the tests means it will be in the interests of our economy, trade, government and public finances and therefore services, citizens, jobs and employers to create a new Scottish currency.”

Tory MSP Adam Tomkins said: "The Nationalists are desperate for independence and they will do or say anything to get it. First their ill-fated White Paper was rejected by the people in the 2014 referendum.

“Then Mr Wilson’s growth commission blueprint for an austerity independence was rejected by his own SNP. Now they’re onto their third attempt to woo voters by pretending that independence is not really independence at all.

“Hospitals are in crisis, teachers are contemplating unprecedented strike action and roads are crumbling - the SNP has many more pressing matters to be focusing on than independence, whatever it is that means this week.”

LibDem MSP Alex Cole-Hamilton said: "With Brexit, the SNP have spent two years setting out the arguments against themselves.

“They have slowly come round to the idea of a people’s vote as it dawned on them that having close ties with our neighbours is a good thing and severing old unions is a tough and fruitless task.

“Andrew Wilson is advocating a soft-independence and a slow transition. Having written the Growth Commission report himself, he knows being out on our own will mean less money in the public purse and poorer public services.

"That’s not good for anyone in Scotland.”

Labour MSP James Kelly added: "The author of the so-called Growth Commission can try and rebrand leaving the UK however he likes, but in reality his plans mean another decade of austerity for Scotland and an economic model that works for big business, not workers."

Pamela Nash, chief executive of the pro-UK Scotland in Union group, said: “There is no such thing as soft independence.

“Independence would involve breaking up the most successful union the world has ever seen, building barriers between families, friends and neighbours.

“It would divide our home market, jeopardising our economy, and lead to further and deeper austerity.

“With the SNP’s proposal to rejoin the EU, an independent Scotland would have to sign up to the euro and there is the very real possibility of a hard border with the rest of the UK.

“Voters won’t be fooled by this – the majority of people in Scotland know we are better off together and want Scotland to remain part of the UK, building a shared future based on economic prosperity.”

Separately, SNP ministers have been criticised for repeatedly refusing to say whether they have taken legal advice on holding a wildcat Catalan-style referendum on independence.

The Scottish LibDems accused the government of “stonewalling” on the issue after the top law officer refused to say whether he had been consulted on the matter.

Responding to a request for details from MSP Mike Rumbles, the Lord Advocate James Wolffe QC said “convention” meant it was inappropriate for him to comment.

“It is however open to you to ask the Scottish Government what its position is,” he said.

But Mr Rumbles said he had already been given the brush-off by ministers.

Theresa May has refused to grant Holyrood a so-called Section 30 order empowering it to hold another legally watertight referendum, leading to speculation about a wildcat vote, such as the one held in Catalonia in defiance of the Spanish government.

Ms Sturgeon has also always said a Section 30 referendum, of the kind held in 2014, is the gold standard, and has show no appetite for a Catalan-style vote.

However Mr Rumbles said: “The Scottish Government are going to outrageous lengths to avoid telling the public what they are plotting behind closed doors. Ministers just shuffle excuses back and forward between themselves. It’s not good enough.

“People have a right to know what their government is up to. Rather than stonewalling, government ministers must return to Parliament to confirm whether they are actively considering a wildcat independence referendum without a section 30 order.”