Andrew Wilson, who penned the recently revised economic blueprint for an independent Scotland - the Sustainable Growth Commission - says this is the way to “win big.”
But the ex-SNP MSP’s comments prompted criticism from pro-union parties who insisted there is “no such thing” as soft independence.
Ms Sturgeon has pledged to set out her timetable for a second referendum in the coming weeks. The pro-independence campaign has faced increasingly awkward questions over the practicalities of leaving a centuries old union, in light of the turmoil engulfing the UK over its looming departure from the EU.
But Mr Wilson sought to play down such concerns in his weekly column for the national newspaper today.
“In the parlance of Brexit, we offer the softest of possible changes to the current arrangements, not the hardest,” he said.
“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.”
Mr Wilson’s prospectus set out plans for caps in public spending in the early years of independence to address Scotland’s deficit and warned against a more radical outlook within the Nationalist movement.
He added: “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.”
But Pamela Nash, chief executive of Scotland in Union, 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.”
Labour’s finance spokesman 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.”