The Green MP for Brighton Pavilion said that she would back a caretaker government led by Jeremy Corbyn to prevent Britain leaving the European Union (EU) without a deal.
Caroline Lucas also urged other MPs to join her in trying to stop Prime Minister Boris Johnson’s Conservative government from pursuing a “no deal” Brexit.
She has accepted an invitation from Mr Corbyn, the Labour leader, to meet next week to “discuss all tactics for avoiding a ‘no deal’”.
She said: “A ‘no deal’ Brexit would be a disaster for this country – and Parliament must prevent it in any way possible.
“Jeremy Corbyn has done the right thing by reaching out to colleagues and I welcome the fact that all the opposition parties in the House of Commons have accepted his invitation for discussions.
“I would urge all MPs who have been approached and who recognise the danger this country faces to join these talks with an open mind.
“We all need to put our country’s future first.
“That means either pursuing legislative measures or a vote of no confidence in a Boris Johnson government, which is showing every intention of driving this country off the edge of a cliff, and replacing it with a caretaker government which is committed to giving the people the right to decide on the Brexit deal.
“I am prepared to support Jeremy Corbyn as leader of this caretaker government, as should any MP who wants to stop a ‘no deal’ Brexit.
“But if he cannot gain the support of a sufficient number of colleagues across Parliament, I hope he will be prepared to back another MP from his party, or another, who can.
“I will ask him again to make his position clear in our discussions next week.
“I will also continue to make the case that we need a ‘people’s vote’ before a general election as the only certain way of ensuring that the British people have the final say on Brexit.”
The Labour MP for Hove, Peter Kyle, who opposes Brexit – Britain’s exit from the European Union – said: “At this eleventh hour MPs must come together to fight the disaster of a ‘no deal’ Brexit which we all know would have unimaginable consequences for our communities and for the country.
“Boris Johnson’s extreme Brexit will damage local jobs, local tourism and opportunities for our young people so every option must now be on the table.
“I’m completely confident that if we work together, Parliament can and will block this impending catastrophe.”