THE financial details of any Tory deal with the Democratic Unionist Party must be made public, Labour’s John McDonnell has insisted.

With talks continuing between the Conservatives and DUP over a "confidence and supply" arrangement to help the UK Government get its legislation through the Commons, Mr McDonnell has written to Philip Hammond, the Chancellor, demanding "transparency" regarding any extra resources made available to Northern Ireland as a result of a deal.

Earlier this week, it was suggested the DUP’s price for propping up Theresa May’s administration was £2 billion extra for the region's public services and infrastructure. The figure was denied by Sir Jeffrey Donaldson, the DUP chief whip, although he did not deny some extra funds were being sought.

In the letter, the shadow chancellor says: "I am writing to call on you, in the interests of transparency, to publish the financial consequences of any electoral deal reached between the Conservative Party and the Democratic Unionist Party.

"There has been speculation in the media about possible additional infrastructure and NHS spending for Northern Ireland or reductions in Northern Ireland rates of corporation tax, VAT and/or Air Passenger Duty.

"It is essential that the details of any agreement are made public,” insisted Mr McDonnell.

He goes on: "Specifically, will any additional spending or tax cuts offered to Northern Ireland be offset through reductions in the Northern Ireland block grant, and if not, how will additional spending be paid for?

"Can you clarify whether any additional spending will be funded from general UK-wide taxation or by increased borrowing or by some other means?"

The DUP has made it clear it will only cut a deal with the Conservatives if it delivered tangible benefits for Northern Ireland in terms of jobs and investment in health and education. Asked what the chances were of an agreement being reached before Thursday’s key Commons vote on the Queen’s Speech, Sir Jeffrey said: “Very good.”