JO Swinson has been accused of “hypocrisy” after the Liberal Democrats backed the principle that a general election victory would be enough to scrap Brexit but a Holyrood poll victory for the Nationalists would not be enough to bring about Scottish independence.

The accusation from the SNP came after the Lib Dem conference in Bournemouth overwhelmingly backed the leader’s proposal that if her party won a majority in the forthcoming General Election, then it would immediately revoke Article 50 and see Britain continue as a member of the EU.

Tom Brake, the party’s Brexit spokesman, opened the key debate, telling delegates that the proposal would mean the Lib Dems’ mission would be to “unequivocally” stop Brexit.

“We will put an end there and then to the Brexit nightmare that is dragging the country down and tearing us apart," he declared.

Lord Campbell, the former party leader, argued that the revoke motion “established our leadership” in the bid to keep Britain in the EU while Chuka Umunna, the party’s foreign affairs spokesman, insisted there was no deal better than the current EU membership and that the revoke motion would “stop this national embarrassment carrying on”.

But a number of delegates disagreed and argued that an election campaign based on revocation would alienate Lib Dem supporters who had voted Leave in 2016.

Sir Simon Hughes, the party grandee, noting how there had been no consultation within the party on the revoke proposal, warned conference it presented the party as “extreme on Brexit when we want to be inclusive”.

To applause, the former Justice Minister, also insisted: “How can we argue against the Scottish National Party policy that if they had a majority at their next election, they should not have the right in Holyrood to decide that Scotland could be independent?”

Later, Ms Swinson was pressed on this point. She insisted Brexit had plunged Britain into a “huge mess” and that, while securing a second referendum was the party’s policy, if there were an election, “we will want to revoke Article 50: if we elect a Liberal Democrat majority government on an election that is fought clearly on a platform of stopping Brexit, then that will deliver us that mandate”.

But pressed on how her party was opposed to the SNP securing Scottish independence simply on the back of an election mandate, the East Dunbartonshire MP said the “situation in Scotland is very different” and stressed the whole country was in the middle of a national crisis and her party was seeking a way out.

“What the idea of indyref2 would be is creating more uncertainty, more confusion, more difficulty in a scenario where we already are experiencing all of that Brexit fall-out; the last thing Scotland needs is to have extra uncertainty of indyref2 poured on top of that,” she added.

But the SNP MSP Tom Arthur declared: “This shows LibDem hypocrisy knows no bounds. This fundamental contradiction is so clear for everyone to see. The Lib Dems think they can treat voters like mugs, but it won’t wash; you can’t pick and choose when to support democracy.”

Angus Brendan MacNeil, the SNP MP who has been pushing for a straight SNP election victory to lead directly to Scottish independence – a policy rejected by his party’s leadership in favour of a second referendum – said: "If Jo Swinson's position is that she gets a direct mandate and leap-frogs the referendum result, then the SNP should do the same. That should be our plan B to the plan A of exhausting the referendum route.

"If we are not granted a Section 30 order, then we should go for it."

The MP for the Western Isles added: "The Lib Dems are guilty of multi-hypocrisies, they say we cannot have another independence referendum but they're happy to cancel the Brexit referendum; it's hypocritical."

This referenced Willie Rennie, the Scottish Lib Dem leader, saying a second independence referendum should be blocked even if the SNP and Greens formed a majority at the next Holyrood election.

The Fife MSP added: “Big bang constitutional change is chaotic, damages the economy and divides the country.”