General election 2019: Conservatives face £70bn manifesto black hole after promising expensive policies without funding them Exclusive: Boris Johnson has laid out a string of pledges which are excluded from his detailed spending plans

The Conservatives face a £70bn black hole in their spending plans after making a string of manifesto promises without explaining how to pay for them.

Boris Johnson has pledged to build dozens of hospitals, create a new rail network and set up a hi-tech “gigafactory” to make electric cars. He is also promising National Insurance cuts, a new system of social care and relief for indebted students.

None of the policies is costed in the party manifesto revealed on Sunday. They add up to £52.2bn in added capital investment, and an extra £20.6bn on the annual bill for day-to-day Government spending according to figures calculated by i.

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Opposition parties said Mr Johnson’s spending plans were “fake news” and claimed he would hit taxpayers. It comes after Labour announced its own £58billion in extra spending to compensate women affected by the rise in the state pension age.

Rail spend

The Conservative manifesto proposed a rise in day-to-day spending of just £2.9bn by 2023/24 as well as £3.6bn in tax cuts. But it also contained a number of policies with no price tag attached.

The biggest is Northern Powerhouse Rail, a new network linking Liverpool to Hull via Manchester and Leeds, which its supporters say will cost £39bn. Other promised capital projects not costed by the manifesto include building 40 new hospitals and the construction of a gigafactory, modelled on those previously built by electric car giant Tesla in the US, to make eco-friendly vehicles and batteries to power them.

Tory sources said future investment plans would be funded by a £100bn pot of capital expenditure, only £22bn of which has so far been allocated to specific projects.

Mr Johnson has promised other policies – including a cut to National Insurance, greater provision of social care and a reduction in student debt – which would add to the annual budget for day-to-day spending. If the Tories are re-elected, Chancellor Sajid Javid is expected to set out the spending increases at future Budget announcements as well as detailing how they will be funded.

‘Fake news’

Labour’s shadow Chancellor John McDonnell told i: “The Conservatives’ manifesto has austerity baked in and is missing any plans for the future of the country – especially the social care crisis which Boris Johnson promised to address.

“It also turns out that the costings document produced alongside it has a black hole of billions of pounds. With no evidence behind any of their figures, it looks like the Conservatives’ fake news approach applies to their manifesto too.”

The Lib Dems’ deputy leader Ed Davey added: “Boris Johnson’s relationship with numbers has all the hallmarks of his relationship with the truth – non-existent. A Farage-facilitated Johnson government means a double-whammy hit to people’s pockets with uncosted spending on top of the Brexit chaos.”

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Labour’s manifesto contains its own spending gaps, including the £58bn the party plans to set aside to compensate the so-called “Waspi women” affected by the rise in the state pension age, which would be funded by extra borrowing. Jeremy Corbyn has also refused to put a price on his plans to nationalise multiple industries, estimated by the Confederation of British Industries to carry an upfront cost of £196bn.

Conservative promises — Where will the money come from?

Northern Powerhouse Rail: £39bn

The Tory manifesto promises: “We will build Northern Powerhouse Rail between Leeds and Manchester and then focus on Liverpool, Tees Valley, Hull, Sheffield and Newcastle.” Transport for the North has estimated the cost of a high-speed link from Liverpool to Hull at £39bn. The money would come from unallocated £78bn capital spending budget, according to the party.

40 new hospitals: £10.2bn

In September the Health Secretary promised to build 40 new hospitals but only allocated £2.8bn, enough for six. The Department for Health calculates the cost for all 40 at £13bn, with most not ready until after 2025.

Gigafactory: £3bn

The manifesto pledges funding for “electric vehicle infrastructure including a national plug-in network and gigafactory”. Each gigafactory – a facility to build electric cars and batteries – previously started has cost around £3.4bn, but the Tories have allocated only £400m for electric car infrastructure. The rest would have to come from the capital budget.

Social care fix: £10.8bn

Boris Johnson has repeatedly pledged to find a long-term answer to the social care crisis, but the manifesto does not propose any specific solutions. Labour’s policy of making all social care free is estimated at £10.8bn a year. The Conservatives insist their plans would be cheaper.

National Insurance cut: £8.5bn

The Prime Minister said he wants to raise the threshold for paying National Insurance to £12,500, which the Institute for Fiscal Studies thinks would cost at least £11bn a year. The manifesto only commits to a rise to £9,500 at an annual cost of £2.5bn.

Student debt interest: £1.3bn

The Conservative manifesto says it will “look at the interest rates on loan repayments with a view to reducing the burden of debt”. Cutting the interest rate from 3 per cent above inflation to simply track inflation would cost £1.3bn a year, the IFS says.