LABOUR chiefs privately admit their hard left 2017 manifesto hid £1 trillion of extra spending with dodgy maths to cover it up, a new book reveals.

And they were left gobsmacked when Tories did not spot the gaping black hole in a massive tactical blunder.

2 Labour were reportedly braced to take a huge backlash for their dodgy sums in their 2017 manifesto Credit: AFP or licensors

An explosive tell-all book about last year’s Election reveals Labour manifesto authors were braced for a blistering assault on their sums, but it never came, in a “huge mistake” by Theresa May.

And leaked internal emails from the run up to the June poll that cost the PM her majority show Labour knew some of the manifesto numbers were "implausible or entirely absent."

Despite that the opposition party continue to claim the political blueprint was "fully costed" and would not cripple the public purse.

Now 'The British General Election of 2017', by respected professors Philip Cowley and Dennis Kavanagh reveals those involved in writing Labour’s big spend and nationalising plans “believe that it would have been possible for the Conservatives to credibly claim there was £1 trillion of spending commitments.”

2 Leaked emails from before the 2017 General Election, where Theresa May lost her majority, show Labour knew some of their sums were 'entirely absent' Credit: EPA One aide told the authors: “It just kept thinking, they’ll tear us apart on this. It was obvious to anyone looked in any detail. But the attack never came.” And the book reports that "one internal email highlighted some of the problems with Labour's cost estimates, including the lack of detail on capital spending, as well as some individual costings that were implausible or entirely absent." During Labour's party conference in Liverpool this week, Shadow Chancellor John McDonnell said he was "embarrassed about how mediocre" their manifesto had been in terms of spending pledges. And he hinted that the document was a mere "first step" toward promising to spend even more taxpayers' cash. Labour leader Jeremy Corbyn vows to end 'greed-is-good' culture and start a 'green jobs revolution' in party conference speech

