"BUCKLING under the pressure" – Westminster parties can't support their indyref2 opposition as more Scots demand change, Ian Blackford says.

The SNP's Westminster leader spoke out after Boris Johnson struggled with the issue in a TV grilling by Sky's Sophy Ridge.

Asked if he would ever grant a Section 30 order to remove legal hurdles for a fresh ballot on Scotland's future, he said: "No, I don't want to have one."

He went on: "I think having another referendum, I don't think people in this country think referendums are very wonderful for harmony.

"We had one in 2014, the British people, the people of Scotland, were told in 2014 that that was a once-in-a-generation event. I don't see any reason to go back on that, on that assurance."

The comments came the morning after 20,000 people filled Glasgow's George Square for The National's Rally: #indyref2020.

Nicola Sturgeon and Patrick Harvie were amongst the Yes movement figureheads to address the crowds.

At the event, Sturgeon repeated her intent to seek a Section 30 order in "a matter of weeks" and lead the country to independence.

Commenting on Johnson's remarks today, Blackford said: "The only people who should decide the future of Scotland are the people of Scotland themselves – not Boris Johnson or Jeremy Corbyn – and after the way Scotland has been ignored over the last few years, it is no surprise that more and more people are reconsidering the option of independence and want to see the people of Scotland given a say.

“The election campaign has barely even begun, and we can already see that the Westminster parties are buckling under the pressure of what is a democratically unsustainable position.

“It may please the Tory rank and file to refuse to give the people of Scotland a say on their future, but senior Tories no doubt realise that what goes down well in the Tory conference hall will go down like a bucket of cold sick on Scotland’s doorsteps in an election campaign."

Appearing on Sophy Ridge on Sunday earlier, Sturgeon said the issue of "who decides Scotland's future is one of the central questions at this General Election".

She insisted that a Scottish majority for the SNP in next month's general election, "that sends a clear message that we want to take our future into our own hands, rather than have Boris Johnson continue to impose a future upon us", stating: "I'm putting a very clear proposition before the Scottish people in this General Election and if - and I take nothing for granted - if the SNP win that election, for any Westminster politician to seek to stand in the way of an independence referendum on that timescale would be seeking to ignore the democratically-expressed wishes of the Scottish people."

Labour shadow cabinet member Rebecca Long-Bailey said her party will not oppose a second referendum if the Scottish Government was to push for one after the 2021 Holyrood election.

While she was clear that Labour wants "Scotland to be part of Great Britain", she added: "Ultimately what we have said is that, after the next Scottish Government elections, if the Scottish Government determine they want to pursue another referendum and they go through the legislative process within their own government to push that forward, than as a government we wouldn't stand in their way."

However, Scottish Secretary Alister Jack said the Tories are fighting to "save Scotland from the uncertainty and the division of another unwanted independence referendum".

Writing in the Scottish Mail on Sunday, he said: "We know that she will use any SNP success to demand a second referendum on leaving our United Kingdom.

"Every vote for us is a vote to say no, loud and clear, to that dreadful prospect.

"We are fighting this election not just to get Brexit sorted, but to save Scotland from the uncertainty and the division of another unwanted independence referendum."

Meanwhile, Scottish LibDem leader Willie Rennie said Labour's comments on a second independence referendum showed Jeremy Corbyn's party could not be trusted to preserve the Union.

He said: "It's quite clear Jeremy Corbyn will break up the UK if it means he can get his hands on the keys to Downing Street.

"The Union isn't something Jeremy Corbyn can barter away for personal power.

"Each and every Scottish Labour candidate should take this opportunity to tell the public whether they would vote for another independence referendum if Jeremy Corbyn instructed them to."