Alex Salmond has suggested the appointment of Boris Johnson as prime minister could be the "material change of circumstances" that triggers another independence referendum.
The former Scottish first minister said Mr Johnson, who is widely tipped as a future prime minister, has previously indicated that he wanted to "severely restrict" the powers of the Scottish Parliament.
Mr Salmond told LBC Radio listeners that no prime minister would stand in the way of another referendum if a majority of Scots indicated that they want one.
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"Once you have that sustained opinion in Scotland, and once you have a vote of the Scottish Parliament, both of which you would have to have, then no UK prime minister is going to gainsay," he said.
"It won't happen. Any UK prime minister will concede and bow to the will and wishes of the Scottish Parliament because the Scottish people are sovereign."
Asked if he had run this assertion by Mr Johnson, Mr Salmond said: "I have had a number of conversations with Boris Johnson, and one or two of them have been reasonably lucid.
"Boris, as he used to say, wanted to if not abolish the Scottish Parliament then to severely restrict its powers, if I remember him correctly.
"I mean, that might well be a change in material circumstances, who knows?"
Mr Salmond said the prospect of another referendum in the next five years "depends on the European referendum", with a vote to leave against Scotland's will seen as "a change in material circumstances" from 2014.
He said: "Nicola (Sturgeon) said that she expected to see another referendum within her term as First Minister of Scotland...which as we all know is going to extend for some considerable time, but nonetheless I rest on the advice of my leader."
He said it would "undemocratic" to deny the Scottish people another referendum if there is a "sustained demand" for a re-run.
He said: "Was it Ernest Bevin who said: 'If you try to think about an elephant in your living room, it's quite difficult to describe but there's no doubt whatsoever when it comes through the door'.
"I think a sustained demand is a bit like that."
Mr Salmond also urged Scots-Americans to reject "the nightmare" of Donald Trump winning the US presidency and getting his finger on the nuclear button.
He said he loses sleep over the prospect of the US businessman, who clashed with him over Scotland's renewable energy policy and its impact on Trump golf courses in Scotland, entering the Oval Office.
Mr Salmond suggested Mr Trump's main Democrat rival Hilary Clinton is "vulnerable" to public criticism, with smears sticking to her like "Velcro" after her long career in US politics.
The SNP MP likened himself to her husband, former president Bill Clinton, as "teflon" politicians regarded with "affection" by the public who are "prepared to forgive them a great deal".
Speaking on LBC Radio, Mr Salmond said "the nightmare gets worse and worse" and urged US citizens to elect "anybody but Donald".
"Let's consider the awful prospect that Donald might actually get his finger on the nuclear button and his bottom on the seat in the Oval Office," he said.
He added: "Hopefully America will redeem its reputation and, in particular, my appeal to Scots-Americans is - just remember that man would let down America just as he has let down Scotland.
"There are few things in politics and life that make me lose sleep, but actually Donald in the White House would be one of them."
He added: "You know how they talk about teflon candidates. Bill Clinton was a teflon candidate ... perhaps myself and perhaps others.
"Basically, nothing ever stuck to them on the basis that the public had some affection for them and therefore were prepared to forgive them a great deal.
"Perhaps that applies to me, it certainly applies to a number of politicians.
"Hilary is not. She is the kind of Velcro candidate. Everything sticks to her.
"She has been around a long time in politics so perhaps you acquire that unfortunate tendency, but for whatever reason she is vulnerable in that sense."