NICOLA Sturgeon has said the demand for a second independence referendum next year will be at the centre of the SNP ’s campaign at a forthcoming snap election.

The First Minister made the comment as she set out why her party was backing a new poll on December 9, arguing it would put Boris Johnson in a weak position given his “do or die” promise that the UK would be leaving the EU on October 31.

Writing on Twitter, she said: “Firstly, we have to ask ourselves what the alternative is. Doing nothing allows Johnson to get his bad deal through (with Lab support) or, even worse, run down clock to end January when No Deal becomes a real risk all over again ... For all his bluster, Johnson would much prefer to fight an election with Brexit already ‘delivered’. An election now would instead force him to explain his failure to keep his October 31 ‘do or die’ promise and also defend his bad deal.”

She added: “Finally, all of this Brexit chaos is being imposed on Scotland against our will. To stop this ever happening again, we need to be independent – which is why the demand for #indyref2020 will be at heart of @theSNP campaign.”

READ MORE: Richard Walker: Join The National's rally to help demand #indyref2020 right​

Johnson is to ask MPs today to back his call for a General Election on December 12, but it is unlikely to be passed as Labour, the LibDems and the SNP will vote against the move.

Instead, both the SNP and LibDems plan to work together to secure an election once a Brexit extension is in place, including bringing forward a bill with a December 9 date for going to the polls, or a no-confidence motion if that fails.

Number 10 hinted it could back the opposition parties' proposal for a Bill, requiring only a simple Commons majority, that proposes an election on December 9 should Labour decline to back the Prime Minister's push for a General Election today.

Ian Blackford told the Sunday National: “What [Johnson] is trying to do is squeeze through his deal in the next couple of weeks, so that we end up in transition, we are out of Europe and then he has an election. That is simply not acceptable.

“If the Prime Minister’s so-called deal goes through, it means we are in transition until the end of 2020 – but the risk of falling out on a No-Deal basis at the end of that is enormous, because it is implicit on him getting a free-trade agreement with Europe over that period.”

READ MORE: SNP and LibDems urge EU: Block No-Deal then we'll get an election

LibDem leader Jo Swinson said she hoped Labour would be able to “support” her party and the SNP’s bid for a December 9 election.

The National:

She told the BBC’s Andrew Marr programme that the Bill, due to be placed tomorrow, takes away the threat of No Deal via a Brexit extension until at least January 31, 2020.

“This removes that threat, so they should be able to support this proposal,” said Swinson.

She added: “This Bill is very straightforward. It would set the date for the next election on December 9. The advantage of the Bill is it would enshrine the date into law.”

MP Chuka Umunna said the LibDems had offered a General Election because it looks “highly unlikely” that a second referendum can be secured under the current Commons numbers. The time frame involved for a December 9 election would not allow Johnson to “ram” through his Withdrawal Agreement Bill before polling day, he said.

READ MORE: Angus MacNeil: SNP proposal for December 9 election is 'madness'

Shadow health secretary Jonathan Ashworth said Labour would “have to consider” a General Election if the EU offered an extension to the UK’s leaving date until January. However, Ashworth called the LibDem and SNP’s plan for a December 9 poll an “opportunistic stunt”.

“I mean it’s entirely ridiculous. It would need cross-party support to get through the House of Commons procedures and then it would be subject to all kinds of amendments, particularly when it gets into the House of Lords. It’s just a stunt so the LibDems can get on the telly today.”

He added: “We have to wait and see what the European Union clarify about an extension date and if they give us that extension until January then we will have to consider it but at the moment we don’t have that clarification and we cannot support Boris Johnson’s plans until we’ve got an absolute reassurance that No Deal is off the table.”

Culture Secretary Nicky Morgan expressed similar sentiments when questioned about the LibDem and SNP offer of an election on December 9.

She told Sky News’ Sophy Ridge On Sunday: “There is a very clear motion tomorrow. If the LibDems and SNP really want an election then they can vote our motion tomorrow.”

She added: “If the SNP and LibDems want an election then they have a chance to vote for one as quickly as tomorrow when the Government’s motion is voted on.”

The UK Government has requested a Brexit extension from the EU until January 31, but is still waiting to hear if it will be granted. If not, the UK will leave the EU without a deal 11pm this Thursday.

The EU27 nations have to unanimously agree to any extension and to how long it would last.