The SNP has urged opposition parties to back a no confidence motion that could remove “zombie prime minister” Boris Johnson from office.
Mr Johnson is facing calls to resign after the Supreme Court ruled that his suspension of Parliament was unlawful.
But opposition parties are split over what to do if he refuses to quit.
The SNP’s Westminster leader, Ian Blackford, said a confidence vote could remove the PM and allow a general election to be held.
Mr Blackford said a “caretaker” prime minister would need to be found if the motion of no confidence was successful – and did not rule out the possibility of Labour leader Jeremy Corbyn filling the role until a general election was held.
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Speaking to the BBC’s Good Morning Scotland programme, he stressed that it was crucial to ensure that the so-called Benn bill, which aims to prevent the UK leaving the EU on 31 October without a deal, is fully implemented and an extension to the Brexit deadline is sought.
But Mr Blackford said the country now had “a zombie prime minister and a zombie government” and called on opposition parties to come together to end Mr Johnson’s tenure in 10 Downing Street.
He added: “We need to make sure we can remove him but a manner which is safe, and we can do that by having a motion of no confidence, and we seize the initiative and move quickly to have an election safe in the knowledge that the extension to the Article 50 process is going to be granted.
“This is a government that shut Parliament down unlawfully and they need to be removed. We need to have that motion of no confidence in a timely manner.
“I’ll be appealing to colleagues and other parties to stand with us to make sure that we show Boris Johnson the door.”
Mr Corbyn has previously said Labour would introduce a motion of no confidence “when we can be confident of success”.
If the Conservative government was to fall as a result of the vote, Mr Corbyn would have 14 days to persuade enough MPs to allow him to head a temporary government that would extend the Brexit deadline before holding an election.
Lib Dem leader Jo Swinson initially claimed Mr Corbyn was too divisive a figure for a caretaker role – but later signalled she was not ruling out the possibility of backing him.
However, she warned on Wednesday against an early vote of no confidence in Mr Johnson, which she said could risk the UK “accidentally crashing out of the EU”.
When asked whether he would be prepared to accept Mr Corbyn as the head of a caretaker government, Mr Blackford said that the focus should be on removing the current prime minister from office rather than on an individual who would temporarily replace him.
Mr Blackford was speaking as MPs returned to the Commons the day after Supreme Court judges ruled unanimously that the suspension Mr Johnson imposed earlier this month was unlawful.
The prime minister cut short his trip to the United Nations in New York to return to London following the court’s judgment, and is expected to face the Commons later on Wednesday.
Mr Johnson spoke to the Queen after the Supreme Court verdict but government sources would not comment on whether he apologised.
Boris Johnson: SNP wants confidence vote to remove ‘zombie’ PM}