The first tranche of the £1 billion secured by the DUP as part of its deal with the Tories is already being spent – despite the fact that Parliament has not authorised the expenditure as the Government said would be necessary.

Amid confusion even in the Cabinet as to how the money which bought the DUP’s votes can be spent, i has established that the first £20 million instalment of the cash is already being distributed by Stormont departments despite the possibility that Parliament might vote not to approve the spending.

Rather than authorising expenditure of the money prior to it being spent, the Government is planning to ask Parliament to approve the expenditure after some of it has already left the Government account – effectively a retrospective process.

The Treasury told i that the “funding committed in the Confidence and Supply Agreement is subject to the full authorisation of the UK Parliament through supply estimates which will take place soon”.

It is understood that the money is likely to next month be bundled in with wider public spending authorisation in what are known as the Spring Supplementary Estimates, a tidying-up exercise which regularises public spending in the final few weeks of the financial year.

What if Parliament said no?

If Parliament rejected the spending of money which had already gone – something which would require a Tory backbench rebellion – it is not clear what would happen.

One source suggested that auditors would class it as irregular expenditure which would then still require retrospective Parliamentary authorisation.

In September the Government’s lawyers had told Gina Miller, who had challenged the basis of the DUP deal, that “additional payments contemplated by the agreement will be authorised by parliament”.

And on Thursday new Northern Ireland Secretary Karen Bradley indicated to i that the money could not be spent unless Northern Ireland ministers were in place, before quickly retracting that and saying that the money could be spent regardless of whether there are ministers.

She said that the first £50 million had been made available to Northern Ireland departments but that only £20 million of that would be drawn down by the end of the financial year on March 31. Speaking of that money, she said the government was “fully committed to making it available”.