A spending row has broken out after the Conservative Party published what it claims would be the cost of a Labour government over five years.
The report, compiled by the party and not the Treasury, is based on a number of commitments from Labour’s annual party conference but not its manifesto.
Chancellor Sajid Javid said Labour’s proposals would leave the UK “on the brink of bankruptcy”.
But shadow chancellor John McDonnell condemned the report as “fake news”.
The Conservatives claim that Labour’s policies would cost £1.2tn over the course of the next five years, if the party wins next month’s general election.
The figure is based on costing Labour’s 2017 manifesto and other pledges it has made since then.
But the Labour Party has yet to publish its 2019 election manifesto, detailing its policies and spending proposals.
Senior Labour figures will meet next weekend to decide which policies passed by the party’s annual conference will become manifesto proposals for government, with some unlikely to be confirmed.
Labour’s shadow communities secretary Andrew Gwynne said the manifesto would be “fully costed” when it is published.
Challenged on the assessment by the BBC’s Andrew Marr, Mr Javid stood by the figures.
He told the programme: “This is the true cost of Corbyn’s Labour. These are the numbers that John McDonnell did not want you to see.”
The chancellor added: “Of course [Labour] aren’t going to welcome these numbers. They don’t want to see this kind of transparency.
“These are eye-watering levels of spending… it will be absolutely reckless and will leave this country with an economic crisis within months.”
But asked about the Conservatives’ own spending pledges – and how they would be funded – Mr Javid only said the party would “set out our plans during the course of the election campaign”.
“Our plans are properly costed and it will be clear how we will be funding that,” he added.
Earlier, business minister Kwasi Kwarteng was pushed for the Conservatives’ spending plans by Sky News’ Sophy Ridge programme, but he said he was “not going to bandy around figures”.
Mr McDonnell branded the Conservative report a “ludicrous piece of Tory fake news” and an “incompetent mish-mash of debunked estimates and bad maths, cooked up because they know Labour’s plans for real change are popular”.
And Mr Gwynne told the BBC’s Andrew Marr show the Conservative claims about Labour spending were “an absolute work of fiction”.
The shadow minister said his party’s proposals would be “open and transparent” on costings, and called on the Tories to do the same with their manifesto.
Neither the Conservatives nor Labour have confirmed a date for when their manifestos will be published.
But the deputy leader of the Liberal Democrats, Ed Davey, has called for both parties to submit their manifestos to the Office for Budget Responsibility to be independently costed.
“The cash commitments that are being thrown around by the two old parties need to be subject to proper scrutiny,” he said.
“Manifestos need to be independently assessed and costed by the Office for Budget Responsibility so that the public can be confident that flagship policies can be delivered.”
Mr Davey said the Lib Dems were “more than prepared” to do the same with their own manifesto when it is published.