The Scottish Government cannot afford to alleviate all of Westminster’s “staggering” cuts in benefits spending, the Social Security Secretary has told MSPs.

Shirley-Anne Somerville said £125 million of Scottish Government cash was going towards mitigating reductions in welfare spending imposed by the Conservatives in London.

She warned work being done by the SNP administration to try to help poorer families could be at risk if ministers in Edinburgh limited their ambition to merely “mitigating the decisions another government”.

Ms Somerville spoke out as MSPs debated a report by Holyrood’s Social Security Committee on the impact of the introduction of the Universal Credit system.

Conservative MSP Michelle Ballantyne conceded the system, which brings several benefits into one payment – including housing benefit and working tax credits – would leave some people “slightly worse off”.

While she stressed the changes were “nowhere near being rolled out to everybody”, Ms Ballantyne said: “There’s no doubt some people will benefit more from the introduction of Universal Credit and others will benefit less, or may indeed be slightly worse off.”

Ms Somerville argued: “There is a growing mountain of evidence that Universal Credit pushes people further into poverty rather than helping them out of it.”

The Social Security Secretary told MSPs: “The support provided by the UK Government to those in low paying work is simply not enough to make ends meet.”

While some powers over welfare have been devolved to Holyrood, she said Scottish ministers were “limited in what we can do with Universal Credit”.

Changes brought in by the Scottish Government mean recipients can opt to have payments twice a month, instead of once a month, as well as having the housing element of Universal Credit paid directly to their landlord.

These have been taken up by 32,000 claimants, with Ms Somerville saying this showed “people do want more flexibility and adaptability in how they receive the support they are entitled to”.

But she told MSPs: “There is no doubt the impact of the UK Government’s cuts are staggering.

“Cuts will amount to social security spending in Scotland being £3.7 billion by 2020-21. 

“We are already spending over £125 million to mitigate some of the worst impact of some of the UK Government’s cuts and to support those on low incomes.”

This includes cash to mitigate the so-called bedroom tax, as well as grants paid out through the Scottish Welfare Fund.

Ms Somerville said: “The Scottish Government, however, is not here simply to paper over the cracks of the UK Government’s welfare cuts.

“We simply cannot afford to cover the costs of billions of pounds of cuts each year.

“I hear regular calls for us to cover the costs of further cuts but no suggestions as to what we should scrap if we were to do so.

“To be clear, every pound we spend offsetting a UK Government cut means we cannot spend that funding on other public spending and priorities.

“I want this Government to be able to invest funds in pulling people out of poverty – that is why we are working hard to develop our new income supplement, which will provide additional financial support for low-income families who are the most at risk from the impacts of the UK Government cuts.

“But we risk all of that if the extend of our ambition is mitigating the decisions of another government.”

Labour MSP Mark Griffin told how the committee had “heard that Universal Credit is not fit for purpose”.

He added: “It is plunging people into poverty, arrears and destitution.”

Alison Johnstone from the Scottish Greens branded it a “significant driver of foodbank use”, while Liberal Democrat MSP Alex Cole-Hamilton said the system had  “wholly failed to make work pay”.