Alex Salmond believes Scotland will be independent within four years and vowed to play “whatever part is necessary” in a second referendum campaign.
The former First Minister said Brexit is the key driving force and will dictate the timing of another independence vote.
Out of political office for the first time in decades, Mr Salmond is hosting a sold-out run of chat shows at the Edinburgh Festival and speaking before his debut performance on Sunday, he said: “I think Scotland will become independent, I think that was rendered inevitable when the Scottish Parliament was established.
“The timing has always been the interesting thing and I think the timing and outcome of Brexit will dictate the timing of another referendum and therefore the timing of independence, in the medium term.
“If Brexit is a soaraway success, the best thing since sliced bread, then I think that will postpone another referendum but I don’t know anyone who thinks that now.
“So therefore I think a (second independence) referendum will be at some point in the next three to four years, depending on the transitional period of Brexit, and I think the result will be a Yes.”
The ex-SNP leader, who lost his seat as MP for Gordon in May’s General Election, said he will play “whatever part is necessary” in a future referendum campaign.
Asked if he could return to elected office, he said: “I’m not ruling it out. The timing is not in my hands, I mean Theresa May didn’t know when the last election was until she was up a Welsh mountain and she probably regrets climbing it.”
In the meantime he is looking forward to hosting his festival show which will feature invited guests, music and comedy.
Mr Salmond said: “There are things you can’t say in office that you can say out of office.
“And there are things you can do out of office that you can’t do in office, not just as First Minister, but as an MP you can’t just swan off to the Edinburgh Festival for a couple of weeks, that’s not fair on your constituents but luckily my constituents relived me of that responsibility and I’m now able to do it.”
He joked he could tour the world with the show if it is received well with audiences, saying: “The global decision comes after the run in Edinburgh.”
The 62-year-old would not reveal any of the guests he has lined up for chats but said his ideal show would feature Donald Trump and Kim Jong Un as their political stand off continues.
Jackson Carlaw, Scottish Conservative deputy leader, said: “It is clear that Alex Salmond has learned nothing from his election defeat. Voters sent a clear message that they are fed up hearing about a second referendum, but it seems Mr Salmond, along with many others in the SNP, are still not listening.”