The Tory party has "failed" the UK and a general election is the "change of direction the country needs", Jeremy Corbyn has said.
The Labour leader said the UK is facing a Brexit "crisis" and will vow to do "everything necessary" to stop the UK leaving the EU without a deal.
It comes after a leaked government report warned of food and medicine shortages in a no-deal exit.
Cabinet minister Michael Gove said it outlined a "worst-case scenario".
Mr Corbyn gave the speech as part of his trip to Northamptonshire.
And shadow chancellor John McDonnell told the BBC that Mr Corbyn will meet other British political leaders next week to discuss tactics to prevent a no-deal Brexit.
He also supported calls for the House of Commons to be recalled "in the next few days" to allow MPs to debate the prospect of a no deal. Parliament could be reconvened if the government put a request in to the Speaker John Bercow.
Mr Gove, who is responsible for no-deal preparation, said the leaked cross-government study, codenamed Operation Yellowhammer, was old and that Brexit planning had accelerated since Boris Johnson became prime minister.
A Downing Street source said the no-deal impact study leaked to the Sunday Times was presented at the first daily no-deal preparation meeting under Mr Johnson's government in July - but it was prepared by the previous administration.
A government source also told the BBC the no-deal study had been leaked by a disgruntled ex-minister in an attempt to influence discussions with EU leaders.
But Lord Kerslake, a former head of the civil service, said the dossier "lays bare the scale of the risks we are facing".