Chief Secretary to the Treasury Liz Truss who has been accused of misleading Holyrood. Picture: PA

Chief Secretary to the Treasury Liz Truss was quizzed by MSPs on the Scottish Parliament’s Finance and Constitution Committee, telling members that SNP ministers had not approached the UK Government for help with their plans to replace Air Passenger Duty (APD) with a new devolved tax.

But a spokesman for Scottish Finance Secretary Derek Mackay insisted that statement was “completely and utterly untrue”.

The accusation came after Scottish Labour alleged that the Finance Secretary misled MSPs on progress towards replacing APD with an Air Departure Tax.

Sign up to our daily newsletter The i newsletter cut through the noise Sign up Thanks for signing up! Sorry, there seem to be some issues. Please try again later. Submitting...

Scottish and UK ministers had previously agreed to delay the introduction of the new levy until issues regarding an exemption for flights departing from Highlands and Islands airports had been resolved.

Mr Mackay had “clearly told Parliament he would ask the UK Government to sort out this mess with the EU Commission”, said Scottish Labour’s Neil Bibby.

• READ MORE: Health secretary writes to EU workers at NHS Scotland over Brexit fears

But when he pressed the Chief Secretary to the Treasury on whether this had happened, she told him: “We are working with the Scottish Government, we have offered to help in terms of approaching the European Union but I don’t believe we have currently been asked to do that on their behalf.”

Mr Bibby described that as an “astonishing revelation”.

The Labour MSP said: “SNP Finance Secretary Derek Mackay clearly told Parliament he would ask the UK Government to sort out this mess with the EU Commission - but the UK Government says that just is not true.”

He added: “That is a shocking situation that once again proves how timid the SNP is in government.”

But a spokesman for Mr Mackay insisted: “This claim is completely and utterly untrue.”

The spokesman said there had been a series of meetings and correspondence between the two administrations on the issue.

Discussions have taken place at both official and ministerial level, the Scottish Government said.

And Mr Mackay is said to have written to the Treasury “explicitly asking the UK Government” to raise the issue with the European Commission on the Scottish Government’s behalf.

The spokesman said: “We have lobbied the UK Government repeatedly on this issue - but it speaks volumes that Scottish Labour would take the word of a Tory minister over that of the Scottish Government.