Welfare cuts announced by George Osborne since last year's General Election will cost Scots £1.1bn a year by 2020, academics have calculated.

Cities like Glasgow will be among the areas hardest hit, according to researchers at Sheffield Hallam University.

But London and much of the south east of England are set to escape the brunt of the impact.

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The SNP said that the estimate laid bare the cost of the Conservative Government's "obsession with austerity".

But the UK Government said its policies were designed to ensure that people kept more of the money they earned.

A spokesman also pointed to new powers soon to be transferred to Holyrood, including the ability to "top up" social security payments and create new benefits.

Yesterday (MON) Scottish Secretary David Mundell said that he looked "forward to hearing from the Scottish Government how they intend to use that power, which they fought so hard to ensure they had".

He also announced that the cabinet minister in charge of the benefits system, Work and Pensions Secretary Stephen Crabb, has volunteered to be grilled by MSPs.

His predecessor Iain Duncan Smith was criticised for snubbing requests to appear before the Scottish Parliament's welfare reform committee.

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But Mr Mundell said that Mr Crabb was “very keen to be available”.

Mr Duncan Smith dramatically quit the cabinet earlier this year in protest at continued welfare cuts.

In calculations presented to MPs last week, Sheffield Hallam researchers estimate that post-2015 cuts will cost Scotland £1.1bn a year by the end of the decade.

Glasgow is among the 40 UK areas that will be hit hardest.

The average cut in the city will be £420 for every adult in work.

Around 350,000 Scottish households will be affected by the changes to tax credits alone.

These reforms, alongside cuts to the new universal credit, a one-stop payment designed to replace a number of current benefits, will affect mainly those on low and middle incomes.

Most of the post-2015 welfare cuts are expected to hit families with children.

On average a couple with two or more children will lose £1,450 a year.

Lone parents with two or more children will lose £1,750 a year.

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Across the UK the post-2015 welfare reforms will take almost £13bn a year from claimants by 2020-21, according to the researchers.

The cuts comes on top of the billions taken from the welfare bill by the Conservative-Liberal Democrat Government between 2010 and 2015.

Professor Steve Fothergill, one of the researchers involved, said: "It will take a while for all these reforms to come to maturity, so by around 2020.

"But this is on top of changes since 2010."

Dr Eilidh Whiteford, the SNP’s welfare spokesman, said: “This report lays bare the Tories’ staggering obsession with austerity of choice rather than necessity and also betrays how poorly thought-out these so called “welfare reforms” are with the gap between the best and worst performing local economies widening even further."

A UK Government spokesman said that it was creating a higher wage, lower tax economy.

He said that the reforms would ensure the welfare system was fair.

The new National Living Wage would boost the pay of up to 6 million people across the UK, he added, while rises in the amount workers have to earn before they pay income tax allow them to keep more of their salary.

He added that the Scotland Act, currently going through Westminster, would transfer new tax and welfare responsibilities to the Scottish Parliament.

The welfare powers, worth around £2.7 billion a year, allow for top-ups to tax credits, universal credit and child benefit.

MSPs will also be responsible for carer's allowance, disability payments, winter fuel allowances, maternity payments and funeral benefits.

The Scottish Government will be able to create new benefits in any area of devolved responsibility.

In its manifesto, the SNP described the welfare powers as "limited" but pledged to increase carer's allowance, restore housing benefit to 18 to 21-year-olds and reform assessments for disability payments.