Scottish Labour shadow finance secretary Jackie Baillie accused the SNP government yesterday of “cooking the books” on oil price forecasts.

Ms Baillie demanded a new Scottish Office for Budget Responsibility (OBR) to be set up to monitor public finances.

A spokesman for Finance Secretary John Swinney — who will present his budget to the Scottish Parliament this week — retorted that Ms Baillie had “some brass neck” as national debt had trebled under Labour.

Ms Baillie said she wanted the new body to scrutinise the manifestos of all the political parties at the Scottish Parliament.

She said: “The way the SNP cooked the books on oil during the referendum proved they can’t be trusted to be honest with the Scottish people about the public finances.

“Scots were misled on oil by the SNP and it must never happen again.”

Labour wants the Scottish OBR to be established in advance of the devolution of new tax powers recommended by the Smith Commission.

“We need to know there is a watchdog holding ministers to account,” said Ms Baillie.

Mr Swinney’s spokesman said the SNP government had already set up a Scottish Fiscal Commission which they now intended to put on a statutory footing.

The government argues that “its remit expand to reflect any new fiscal powers” devolved to the Scottish Parliament.

“It takes some brass neck for a Labour politician to accuse others of making over-optimistic fiscal forecasts,” the spokesman added.

“In just six years, Gordon Brown managed to get his borrowing predictions wrong by over £400 billion — and of course, during Labour’s time in office national debt almost trebled.

“In contrast the SNP government has balanced the budget every year.”