A ROW between the SNP's finance secretary and one of Holyrood's most influential committees has erupted into the open due to the amount of time that will be available to scrutinise the most important Scottish budget ever.

Derek Mackay was last night rebuked by SNP colleague and finance committee convenor Bruce Crawford, who accused the Scottish Government of reneging on pledges to publish preliminary information that would have highlighted proposed spending priorities from next April.

The Scottish Government has blamed delays in the UK Government's Autumn Statement for the hold up in publishing its draft budget, which will include unprecedented tax, spending and welfare decisions following the devolution of new powers to the Scottish Parliament. Mr Mackay has argued that the UK figures will be needed before he knows how much he will have to spend, with the EU referendum result only adding to uncertainty.

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However, Mr Crawford has claimed that the timetable will leave just a fortnight to scrutinise a budget far more complex than Holyrood has ever seen before, despite in previous years months being available for the process.

Typically, the Scottish budget is published in draft form each September or October, giving MSPs time to study its implications and inform a budget bill issued in January. But this year, Mr Mackay plans to reveal his proposals in the week of December 12, allowing only two weeks for scrutiny when the Christmas break is taken into account.

The dispute comes amid growing calls for Holyrood's committees to adopt a more autonomous and challenging role to Government, amid fears that a weak parliament has led to the passage of inadequate legislation, such as the named person law that was recently ruled to be illegal. Mr Crawford's criticism of the Government was unanimously agreed by the 11-person committee, which includes four other SNP MSPs.

Mr Crawford said that allowing appropriate time for scrutiny is "essential" with appropriate committees usually taking evidence and engaging with interest groups about budget proposals. While he accepted that in light of Brexit Mr Mackay had an "arguable case" when calling for a delay, he said it must not become a precedent and a refusal to provide even preliminary information, despite previous indications that it would be made available to committees, was "unacceptable".

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In his letter to Mr Mackay, he said: "Given the proposed heavily truncated timetable the Finance Committee has sought to work with you in considering what level of information could reasonably be provided to support effective parliamentary scrutiny prior to the draft budget being published.

"In particular, you informed the Committee on 7 September that 'I am willing to produce as much scenario planning information as I can.' The committee clerks and your officials subsequently held discussions around the possibility of scenario planning.

"It is, therefore, unacceptable that you have now informed the committee that you are not prepared to publish any such scenario planning information in advance of the publication of the draft budget. The Committee considers that without such information and illustrative figures it is unlikely that there will be sufficient opportunity for the subject committees to robustly scrutinise spending proposals in their respective portfolios."

The finance committee has lodged a motion calling for a Holyrood debate over the timetable for the 2017-18 draft budget, in a bid to heap pressure on Mr Mackay. However, the publication date is ultimately a matter for the Government.

Murdo Fraser, finance spokesman for the Scottish Tories, called on the SNP leadership to back down. He added: "The SNP is now a minority government and can't simply force through what it wants. Today, Derek Mackay is learning that very lesson."

Scottish Labour business manager James Kelly said: "The SNP have form for trying dodge parliamentary scrutiny, they cannot repeat those tricks when it comes to the funding for Scotland's public services."

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Mr Mackay has previously warned that the UK autumn statement, due on November 23, would see a 'significant shift' in UK tax and spending plans because of Brexit.

A Scottish Government spokeswoman said: "We welcome the Finance Committee's recognition that the fiscal and economic uncertainty caused by the outcome of the EU referendum and the complex relationship between the Autumn Statement and the Scotland Act 2016 powers necessitates a later publication of the Draft Budget.

"We recognise that moving to a post-Autumn Statement publication date would represent a change to previous years, but the Finance Committee acknowledges that a number of subject committees have already adapted their approach to budget scrutiny ahead of any Draft Budget publication to ensure that effective scrutiny takes place."