This article was first published on 21 April 2021 and some Scottish election polls mentioned have moved on since then.
It is also possible that Scottish Labour may do well enough in the ballots to overtake the Scottish Conservatives to become the second largest party in Holyrood.
“It’s inconceivable that we are going to get anything other than an SNP administration,” Sir John told NationalWorld.
“The question is, is it a minority one or a majority one? That, potentially, is pretty important.
“The truth is, we’re talking about a country where half of the public are in favour of independence, and most of those voters - about 88 to 89 per cent - are inclined to vote for the SNP.”
Will the SNP get a majority?
He added: “As a result, the SNP dominate with much of the yes vote, whereas the Unionist voters are fragmented between Conservative and Labour.
“But, could in the next couple of weeks support for the SNP just dip a little so they don’t get an overall majority? Yes, that is perfectly possible.”
The current polls at the time of writing show Nicola Sturgeon’s party way ahead, particularly in the constituency vote where they are running on an average of 50 per cent.
But Sir John said the SNP can’t be “as explicit as [it] would like to be” that it is seeking an overall majority to hold another independence referendum.
Instead, the party is forced to say that any majority would be a sufficient mandate as that is a possible outcome of the election.
Either way, Sir John believes that support for independence is unlikely to fall in the near future - thanks to Brexit.
“The issue is not going to go away because of Brexit. Brexit is what has put new fuel in the tanks, and it is Brexit that is responsible for the fact we now have a country with about 50 per cent support for independence.
“Unless it proves to be successful then it is difficult to see how support for independence is likely to fall any time soon.”
What’s the outlook for the Alba Party?
Pro-independence voters now have another option on the regional list ballot due to the launch of Mr Salmond’s party less than two months before the 6 May election.
And Sir John suggested that the former First Minister’s intervention could make reaching an overall majority more complicated for Nicola Sturgeon.
However, he adds, most polls at the time of writing say Alba “is going nowhere” - although Mr Salmond may end up being elected himself.
“Alex is very unpopular, including people thinking, ‘Why the devil is he doing this?’, but also because they don’t think his intervention is helpful.
“I think what we can rule out is the idea that the Alba Party is going to get well above 10 per cent [in the regional list vote] and that it is going to be a significant presence in the new parliament.
“Alex has got more coverage than expected - he’s been on Good Morning Britain, Good Morning Scotland, STV - and he’s done quite well for a party that’s got no electoral record at all.
“But that doesn’t seem to be suggesting that the party is having a major impact on the election.
“Most polling says that they will, at most, just end up with Alex elected.”
Could Scottish Labour overtake the Scottish Conservatives?
Meanwhile, Sir John believes that Scottish Labour are potentially able to overtake the Scottish Tories when voters go to the polls.
The Conservatives, led by Douglas Ross, are running at about 21 per cent in predictions at the time of writing, while Anas Sarwar’s party are at about 18 to 19 per cent.
“The gap between them is not that large,” Sir John said.
“The Conservatives are going to struggle to get much more than low 20s for votes as they’re very much fishing in the niche market of people who voted both No and Leave.
“Labour might just be able to do well enough to overtake them, but it’s going to be quite difficult.
“There’s not much sign so far of the party making any progress, although the Tories have fallen back a bit.”
It is also “pretty clear” that Mr Sarwar is a more popular leader than Mr Ross, Sir John said - but at the moment there is no sign that that personal popularity will translate into increased support for Scottish Labour.
The Scottish Greens look to be the favourite to come fourth in the election, with nine to 10 per cent of the vote, while the Liberal Democrats are “flatlining”, he added.
Things ‘unlikely to change’ before vote
The May election all comes down to a “fundamental division”, the polling expert said.
“Even on the list vote, there are very few No voters that are going to vote for the SNP, the Greens, or Alba.
“And there are very few supporters of independence who are going to vote Conservative, Labour or Liberal Democrat.”
But when voters in Scotland cast their ballots, these nuances are diminished and only one thing is important: the election result.
Are voters likely to change their minds in the lead-up to polling day?
“A dominant SNP, a pro-independence majority of MSPs and a pretty fragmented Unionist movement - all those things are very unlikely to change in the course of the next few weeks,” Sir John concluded.
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