Scottish Secretary David Mundell has called on SNP Ministers to reveal their plans for benefits and the associated “price-tag” if MPs approve the Scotland Bill in today’s vote in the House of Commons.
Labour also renewed its call for the nationalists to explain how they will use the powers to mitigate the UK Government’s tax credit cuts in Scotland.
First Minister Nicola Sturgeon has pledged to counter the changes if they are pushed through by Chancellor George Osborne, but has not yet given details of what form this would take or how it would be paid for.
The SNP wants the legislation to devolve tax credits in full, and has also tabled amendments for control over equalities legislation and the power to hold referendums.
• READ MORE: SNP ‘should disclose plans for new welfare powers’
The party says the Bill still falls short of the cross-party Smith Agreement on further devolution, brokered in the wake of last year’s referendum on Scottish independence.
But Mr Mundell insisted that Holyrood was “on the cusp” of becoming one of the most powerful devolved parliaments in the world.
MPs will also consider around 80 amendments laid by the UK Government last week aimed at strengthening the legislation.
He said: “Even the Scottish Government now accept that the Scotland Bill gives them substantial new powers over benefits.
“It allows them to top-up tax credits, top-up child benefit or even create brand new benefits in devolved areas.
“The vote in the Commons will mean the Scottish Government have run out of excuses for not telling Scotland what their benefits plans are.
“People now want to know how much this is all going to cost and how it will be paid for. Every extra benefit has a price tag. That is a fact of life.
“Topping up the tax credits of Scottish families would have a cost. Trebling Jobseekers Allowance would cost Scottish taxpayers. We need to know what the cost would be and how it would be paid for.
“If the legislation gets the green light in the Commons today then Scotland is entitled to know what the cost is well ahead of the Holyrood election in May.”
• READ MORE: Mundell confident of ‘fair’ deal over new powers
Labour’s shadow Scottish secretary Ian Murray MP said his party had been the “driving force” in ensuring that the vow on more devolution made to Scottish voters by the three UK party leaders in the days before the referendum had been “delivered in full”.
He said: “The challenge now is to the SNP Government to tell us how they are going to use these powers.
“These powers create an incredible opportunity for Scotland, and we need politicians with the political will to use them.
“As a first step, Nicola Sturgeon should be telling people across Scotland how she will use the powers to restore the money lost from tax credit cuts.”
A spokesman for Ms Sturgeon accused Mr Mundell of “sheer hypocrisy” and pointed out that the Bill will give Scotland responsibility for just 14% of welfare spending.
He said: “The Scottish Secretary - perhaps he’d be better known as Mr Cutter - points out how many Scots receive tax credits, while ignoring the fact that his Government is planning to slash them.
“Last week, after months of pressure, the UK Government lodged over 80 amendments to try and bring the Scotland Bill up to scratch.
“These are welcome, but there are still shortcomings, and Holyrood will make a final decision on the Bill in a few months’ time.
“The final vote will depend on the outcome of negotiations between the Scottish Government and the Treasury, on the funding framework that comes with it.
“The UK Government retains effective vetoes in many areas, and the powers of conditionality and sanctions which will hurt the most vulnerable hardest will remain at Westminster.“