Mr Sillars, who has often been critical of First Minister Nicola Sturgeon’s approach to Brexit and a potential second referendum, made suggested in the National newspaper that the SNP should be willing to trade their support for a Brexit deal for new powers at Holyrood.

Theresa May’s deal is unlikely to return to the Commons before March 29 after yesterday’s intervention by Commons Speaker John Bercow - meaning a delay to the process is now expected.

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There are signs, however, that support within parliament for Mrs May’s deal is increasing, with several Brexiteer Conservatives apparently willing to back the deal in order to avoid that delay.

Mr Sillars told the National: “What about looking for the need for more powers for Holyrood?

“On tax for example, we don’t have the power over pay as you earn, dividend payments, capital gains or National Insurance contributions.

“So yes - ask for a package of new powers - including the right to decide when to have a referendum - but also further economic powers. That would be a good trade off and I would back that.”

The former MP suggested that such a trade off would give the Scottish Government more flexibility regarding the date of a future referendum, in contrast to a temporary transfer of powers under a ‘Section 30’ order, which is Nicola Sturgeon’s preferred option for a re-run of the 2014 vote.

Brexit: Jim Sillars urges SNP to back Theresa May’s deal