SNP demands review of £1bn DUP deal as Mundell comes under pressure

● Scottish Secretary denies claims he forecast cash windfall ● Holyrood and Cardiff launch formal complaint to Treasury

David Mundell has faced down calls to quit over his role in the UK government’s decision to hand Northern Ireland £1 billion of public money in exchange for the support of the Democratic Unionist Party.

The Scottish Secretary insisted that he hadn’t suggested Scotland would see a cash windfall from the deal, which will not see funding for Northern Ireland matched anywhere else in the UK, and said the agreement did not undermine the Barnett formula that calculates the size of Scotland’s block grant.

The UK Treasury said it would respond to a formal complaint about the decision lodged by the Scottish and Welsh finance secretaries.

Mr Mundell came under pressure from the SNP after saying before the deal was signed that he was “not going to agree to anything that could be construed as back door funding for the DUP”.

SNP Westminster leader Ian Blackford said Mr Mundell’s position was “untenable”, and Scottish finance secretary Derek Mackay accused Mr Mundell of being “incompetent, ill-informed and incommunicado” after waiting more than 24 hours before commenting on the deal.

Last night Mr Mundell said: “I was very clear that any arrangement had to be absolutely transparent – it is. I was clear that it had to be subject to the Barnett rules – it is.

“I was also clear there should be no subversion of the Barnett rules, and that hasn’t happened.”

The Scottish Secretary said he“always”arguesforresources for Scotland, and added: “Only a year ago the SNP were arguing that we should give up the Barnett formula and that we should have full fiscal autonomy which would’ve cost Scotland billions.”

SNP MP Pete Wishart, who failed in a bid to call an urgent debate in the House of Commons on DUP deal money, claimed Mr Mundell’s comments show he “failed to lift a finger” to secure additional investment for Scotland.

Earlier, a Downing Street spokesman said the deal with the DUP had the unanimous support of the UK cabinet, and that the Prime Minister “of course has full confidence” in Mr Mundell.

The SNP has argued that the £1bn for Northern Ireland should mean Scotland getting £2.9bn if the funds were distributed by the Barnett formula.

The formula ensures that if funding goes up in England, there are consequentials for the devolved nations.

The extra cash negotiated by the DUP will not be handed over via Barnett, but sees an increase in Northern Ireland’s block grant.

At a cabinet meeting yesterday, SNP ministers agreed to invoke a “dispute resolution mechanism”throughthejoint Ministerial Council (JMC), the body dealing with relations between the UK government and devolved administrations.

Nicola Sturgeon’s spokesman said the cabinet had “expressed its displeasure at the nature of the deal with the DUP, which would appear to be a gross breach of established principles of devolution”.

In a letter to the Chief Secretary of the Treasury, Liz Truss, Mr Mackay said the Scottish Government “fundamentally disagrees” with the way funds werepromisedinthedupdeal and claimed the arrangement breaches rules governing the Barnett formula.

0 Sinn Fein’s Gerry Adams, centre, flanked by, from left, the party’s Northern Ireland leader Michelle