In her first major speech as party leader, Ms Swinson said the Commons needed to win a vote of no confidence against Boris Johnson and within 14 days install a new PM who has "the confidence of the House and will stop a no-deal Brexit".
In a letter to other opposition leaders and leading rebel Conservatives, Corbyn said his plan "can halt the serious threat of no deal, end the uncertainty and disarray, and allow the public to decide the best way ahead".
In this letter Corbyn proposed setting up a temporary and time limited government, under Corbyn himself as a caretaker Prime Minister, to get an Article 50 extension and start the process for a General Election.
And Jo Swinson, the Liberal Democrat leader, said: "A no-deal Brexit must be taken off the table".
He said that Labour would then campaign in the election for a second referendum on the Brexit terms, including an option as to whether Britain should remain after all. The Independent Group for Change, a group of pro-remain members of parliament, made similar comments, suggesting they would not support any political moves that fail to secure a "people's vote".
Johnson has refused to rule out suspending Parliament if legislators try to delay or prevent Brexit. "We may need an emergency government to resolve it but if Jeremy Corbyn truly wants that to succeed, surely even he can see, he cannot lead it", she said. "To set the bar for negotiations so high that we inevitably leave without a deal would be a betrayal".
However, there could be a glimmer of hope for Remainers: the leaked document reportedly says that while Berlin does not expect a sudden volte-face on the part of Mr Johnson's "hard negotiating position", there is an expectation that he may open up a new line of discussions in the upcoming G-7 summit in France.
Referring to Mr Johnson's Brexit plans, West Bromwich East MP Mr Watson said: "To stop him, everyone who cares about democracy, our country and our future must work together, because there are enough of us from all parties in Parliament to stop him".
"There's a bad kind of collaboration going on between people who think they can block Brexit in Parliament and our European friends", the prime minister said in a Facebook Live broadcast on Wednesday.
Even Tories who are vehement opponents of Brexit would struggle with the idea of making the most socialist leader Labour has had in decades prime minister.
Hammond criticized Johnson's government for perpetuating "myths" that the British people voted for a no-deal Brexit and that leaving the European Union without a negotiated settlement would be painless.
She said the notion could prevent Johnson from calling a general election for after October 31.
Costa, a long-time campaigner on citizens' rights, said he wanted Johnson to honour a personal promise given to Costa that rights would be entrenched, saying the only way to do so was through legislation prior to the UK's departure from the EU.
In a dramatic further development, Jeremy Corbyn, leader of the Labour Party announced on Wednesday that he would put his name forward as an interim Prime Minister should there be a successful no confidence vote in Boris Johnson's administration in early September.
"The queen acts on the advice of her prime minister and will keep out of things", said constitutional expert Vernon Bogdanor.