DAVID Mundell was compared to a “demented Grand Old Duke of York” after insisting he did not need to resign over Theresa May’s Brexit deal.

During Scottish Questions in the House of Commons yesterday, the Tory minister was asked by MPs from all parties why he had not yet quit from his position in the Cabinet.

SNP, Labour and DUP frontbenchers took aim at the Secretary of State for Scotland.

They argued that he has broken commitments to stand down if the Government’s Brexit deal meant a differentiated deal for Northern Ireland or an agreement which locked Scottish fishermen into the Common Fisheries Policy (CFP).

Pointing out how the backstop deal would lead to both these outcomes, the SNP MP Tommy Sheppard asked, “how can he justify remaining in the Cabinet?”

“He has publicly refuted the differentiation on which this Withdrawal Agreement is based, he has threatened to resign on numerous occasions.” Mundell, however, said that his position was “quite clear”.

“The SNP and Nicola Sturgeon see Brexit as an opportunity to break up the UK, so above all else I put that first,” he added.

Scottish Labour’s Lesley Laird said Mundell’s “so-called red lines were written in invisible ink”.

The SNP’s Pete Wishart compared the Tory to a “demented Grand Old Duke of York” who had led his “merry band of Scotch Tories halfway up resignation hill and then forgotten whether he is going up or down”.

Mundell said: “There is no greater expert in this House on being ridiculous than him, swinging one way and another on every issue of the day.”