TORY plans to reject full fiscal autonomy are based on “the politics of fantasy and fear”, according to the SNP.

Speaking ahead of today’s House of Commons debate on the Scotland Bill, Tory Secretary of State David Mundell said the UK Government would not accept changes to the bill to allow Holyrood to have full-tax raising and tax-spending powers.

Mundell said: “This Government will not accept amendments that are not good for Scotland. Full fiscal autonomy would be bad for Scotland – leaving us with £10 billion less to spend.

“To put this number into context – last year the Scottish Government spent £10 billion on education and justice, this is everything from schools and colleges to our police force, prisons and court service.

“The Scotland Bill will provide the Scottish Parliament with substantial tax and VAT powers worth around £15 billion and I look forward to discussing the tax sections of the Scotland Bill in detail with members across the House of Commons. This is a ‘deal or no deal’ moment for the fans of full fiscal autonomy.

“They can either vote for a more powerful Scottish Parliament that shares risks and resources with the rest of the UK or they can support a black hole plan that would cost Scotland the same amount as we currently spend on education and justice combined.

“Most would consider this a bit of a no brainer.”

SNP deputy leader Stewart Hosie was incredulous at Mundell’s intervention.

“Mr Mundell’s claims are patently ludicrous,” said Hosie.

“The UK had a deficit of around £75 billion in the most recent financial year – so by the Tories’ bizarre logic, Westminster would have had to raise taxes by £75 billion in a single year to be financially viable.

“We have made our commitment to fiscal autonomy clear – but the Tories should just get on with delivering the powers the people of Scotland were promised instead of indulging in the politics of fantasy and fear that were so roundly rejected at the ballot box last month.”

The Dundee East MP said it was ridiculous to suggest Scotland was incapable of financing itself as an independent country: “Scotland already more than pays its way, with more revenue generated per head than the UK for every one of the last 34 years.

“But we need significant new powers over our economy, job creation, welfare, wages and living standards if we are to make the most of our nation’s potential.

“As for oil, this week’s report shows that Scotland remains, by some margin, the biggest oil producer in the entire European Union – no other country in such a position would have it suggested that it could not finance itself.”

Over the weekend both Scottish Labour and the SNP revealed plans to amend the Scotland Bill’s welfare provisions.

SNP amendments would remove any of the Westminster vetoes on welfare powers and give Holyrood additional powers over working age benefits and benefits relating to children, control over National Insurance, employment law and equal opportunities.

Labour’s amendments would allow the Scottish Parliament to create new benefits, have the final say on benefit rates and top up reserved benefits.

Labour also renewed their call to establish a Scottish Office of Budget Responsibility. Sole Scottish Labour MP, Ian Murray said the debate around the Scotland Bill had been found wanting: “The way the debate has progressed so far hasn’t covered anybody in glory. Too often it has seemed that getting one over on opponents is more important than getting the best deal for families in Scotland. People deserve better than that.”

“Our amendments to the Scotland Bill have one single purpose in mind – to improve the lives of families in Scotland. They will secure the money available for public services and protect the most vulnerable people in our country. That was the original purpose of devolution and it’s what we should be fighting for as we debate the Scotland Bill as the party of devolution.”

SNP leader in Westminster Angus Robertson hoped that the other “anti-Tory” parties in the House of Commons would support his party’s amendments which he claimed would help reduce child poverty.

In an interview published in yesterday’s Observer, Robertson said there would be a referendum in the next five years if David Cameron failed to hand over substantial new powers to Holyrood.

When asked about the possibility of a referendum before the Prime Minister stands down in 2020, he said: “I think that largely lies with David Cameron.

“He has to make a decision as to how he is going to approach governing Scotland with only one MP, having made a cast-iron promise and an undertaking to deliver on more powers for the Scottish parliament and voters.”

An independent Scotland, Robertson said, was an inevitability.

He added: “Do I believe that in the future there will be further moves towards Scottish self-government? Yes, I do.

“Do I believe that there will in time be a growing desire in Scotland for independence? Yes, I do. Do I believe that in time there will be a referendum when the public wants it on independence and that there will be a Yes result? Yes, I do.”