NICOLA Sturgeon is facing criticism from within her own Westminster group over a plan to join the Liberal Democrats in a bid to have a general election on December 9.

The First Minister’s proposal was attacked by SNP MP Angus Brendan MacNeil, who said he would not vote to give Mr Johson his “desired present” for Christmas.

Mr MacNeil, a previous critic of Ms Sturgeon’s approach to Brexit, argued it would be better to keep Mr Johnson “in a cage”, rather than let him win an election and get a hard Brexit.

He also warned that the SNP would be likely to lose its place as the third largest party in Westminster in an election because of a surge for the Liberal Democrats.

“This MP ain't joining with the Lib Dems in their latest coalition bid with the Tories!!” the Western Isles MP tweeted.

Mr Johnson will ask MPs tomorrow to agree to an election on December 12 in return for giving them until November 6 to scrutinise and approve his Brexit deal.

However there is little opposition appetite for giving him a win on Brexit, and he is likely to fall short of the two-thirds majority he needs under the Fixed-terms Parliament Act (FTPA).

EU leaders, who have been asked formally by the PM to delay Brexit until January 31, are waiting for the outcome of the vote before announcing the length of the extension.

Anticipating defeat for Mr Johnson, the LibDems and SNP plan to table a Bill on Tuesday for a one-off amendment to the FTPA for an election on December 9 instead.

This would only happen if EU leaders granted an extension until at least January 31, and Mr Johnson would not be able to “get Brexit done” before going to the polls.

Crucially, this would only require a simple majority of MPs to succeed, meaning it could pass with Tory, SNP and LibDem votes, even if Labour opposed it.

Tory ministers dismissed the idea as a “stunt” and a “gimmick” on Sunday TV shows.

However it was later reported that Downing Street might back the SNP-LibDem plan if it failed to get an agreement on its preferred route to an election tomorrow.

Mr MacNeil made his opposition plain in a series of angry posts on Twitter.

At 10.06pm on Saturday, he said he was glad the SNP had previously ruled out a December election, saying “let Boris stew and make sure we cannot be tethered to a No Deal Brexit - that [is] something we can do while Parliament has Boris Johnson in a cage”.

But just 10 minutes later, he reacted to the SNP/LibDem plan being reported online.

He wrote: “I am not getting bounced in to this... [On] Thursday it was ‘madness’ to have a winter election. Any election now will be a Proxy Brexit referendum and Hard Brexit could be won in 6 weeks on only 35% to 40% of the vote!!”

“Tories have been desperate to amend the FTPA! BUT don't have numbers - even DUP won't help them Now suddenly this [the SNP/LibDem plan] HALF WAY through a Parl term, to give Boris election he craves. SNP won't even be 3rd party after & Boris in crazy atmosphere could have Maj on 35% for ANY Brexit.”

Councillor Chris McEleny, the former leader of the SNP opposition on Inverclyde, added: “An election will give Tories even greater strength to deliver toxic Brexit. Election should be about independence, not about Brexit, in Scotland.”

Ms Sturgeon later defended the plan in a series of tweets this morning, saying it would stop the Prime Minister getting his Brexit deal passed with the help of rebel Labour MPs.

She warned doing nothing would allow Mr 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”.

She said there was “no evidence” a majority of MPs would back a second EU referendum.

She wrote: “We have no time to waste. 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 31 October ‘do or die’ promise and also defend his bad deal.

“To change the course Johnson is taking us on, we need to beat him. I accept that challenge for the SNP in Scotland. Other parties have to do the same elsewhere in UK. Doing nothing almost guarantees he gets what he wants - Brexit delivered, possibly through ‘no deal’.”

She added: “There are undoubtedly pros and cons but, assuming extension for Jan 31 secured, the case for acting now is strong.”