Jeremy Corbin has called on the leaders of other opposition parties and Tory rebels to install him as an PM officer to stop the fruitless Brexit.
If he wins a no-confidence vote in the government, Labor plans to postpone Brexit, call early elections and campaign for a new referendum.
Mr Corbin outlines his plan in a letter, saying that the care government will be "severely limited in time".
Liberal Democrat leader Joe Swinson dismissed the plans as "nonsense".
Downing Street said Mr Corbin would "repeal the referendum and destroy the economy" if he became prime minister.
Prime Minister Boris Johnson says he wants a deal with the European Union, but insists that the UK must leave the bloc by October 31
In order to defeat the government, he will have to secure the support of a majority of MPs.  In his letter, Mr. Corbin writes: "This government has no mandate for a fruitless deal and the 2016 referendum did not mandate an inaction.
"Following a successful vote of no confidence in the Government, I, as the leader of the opposition, will seek the confidence of the Strike Chamber, a provisionally limited interim government, in order to call a general election and secure the necessary extension of Article 50 to do so. . "
If he manages to call a general election – which will require the support of two-thirds of MPs – Labor will campaign for a second referendum with the ability to remain in the EU, he said.
How did the party leaders respond?  Ms Swinson rejected his proposals directly, saying: "Jeremy Corbin is not the person who can even build a temporary majority in the House of Commons for this task"
The letter was also received by Tory MPs Dominic Greve, Sir Oliver Letwin and Dam Caroline Spellman, MEPs Caroline Lucas and Nick Bowles, the independent MP who left the Tory party for Brexit.
In response to the letter, a spokesman for No 10 said: "There is a clear choice: either Jeremy Corbin as prime minister to overturn the referendum and disrupt the economy, or Boris Johnson as prime minister to respect the referendum and deliver more money to the NHS and more police on our streets.
"This government believes that people are the masters and the votes should be respected. Jeremy Corbin believes that people are servants, and politicians can overrule public voices they dislike. "
This comes after the prime minister accused MPs" who think they could block Brexit "of" terrible co-operation "with the EU
Mr Johnson said the EU had become less willing to compromise
He said that it increased the likelihood of the UK being "forced to leave without a deal" in October.
Mr Johnson wants the EU to remove the plan to suspend the Irish border from the deal of its predecessor Teresa May, which was rejected three times by Parliament.
- Johnson: Preparing for non-negotiable deals is a "top priority".
But the EU continues to push for a policy – designed to ensure that there is no hard border on the island of Ireland – must remain and cannot be changed.
What is a no-confidence vote?
If the government loses a no confidence motion, it has 14 d Ays to win the confidence of the House of Commons.
If Mr Johnson fails to win such a vote, a general election will be called.
The Prime Minister has a working majority of only one in the House of Commons. , with the support of the Democratic Unionist Party of Northern Ireland.
What is a no-confidence vote?