CLAIMS that immigration undercuts wages “flies in the face of the evidence”, one of the UK’s top economists has said.

Professor Sir Anton Muscatelli, principle of the University of Glasgow, said there was nothing to support fears overseas workers drive down standards.

It comes just days after UK Labour leader Jeremy Corbyn was criticised for insisting his party’s Brexit vision must include barriers to prevent employers "being able to import cheap agency labour".

First Minister Nicola Sturgeon accused him of echoing former Ukip leader Nigel Farage, and senior figures in his own party also condemned the remarks.

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Sir Anton told Holyrood’s economy committee: “There’s absolutely no evidence and to suggest that there is an impact frankly flies in the face of the evidence.”

He was one of a series of experts to warn leaving the European single market after Brexit would be a “disaster” for Scotland’s economy.

He added: “Unless we are members of the single market, I do think most of the analysis I’ve seen suggests that would be pretty disastrous in terms of GDP loss.

“Being part of the single market is absolutely critical to the economic future of Scotland.”

Professor Sara Carter, who was also quizzed by MSPs, echoed his views – insisting leaving the single market would be “nothing short of a disaster”.

She said: “Brexit was a disaster and the idea that we could even contemplate leaving the single market is similarly disastrous.”

She added: “The whole idea of coming out of the single market puts us in an extremely vulnerable position.”

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Both Labour and the Conservative Government insist the UK needs to leave the single market after Brexit.

But Labour’s position has caused controversy among senior figures, who unsuccessfully pushed for a vote over the issue at the party’s recent Scottish conference.

Former Scottish Labour leader Kezia Dugdale, co-chair of campaign group Scottish Labour for the Single Market, said MSPs had now been told “in no uncertain terms of the catastrophic economic consequences” of leaving the single market.

She added: “This would have a devastating effect on people’s livelihoods, putting jobs and businesses at risk.

“If we are to leave the EU, the only way to protect workers is to remain in the European single market and the customs union. With political will, there is still time to prevent this disaster.”

A Scottish Labour spokesman said the party believes bosses have abused the EU’s posted workers directive – which governs how employees temporarily sent to work in other EU countries are treated.

He said this “hyperexploits migrants and undercuts wages and conditions”, adding: “As Jeremy Corbyn said in his speech in Coventry on Brexit earlier this year, ‘Let’s be crystal clear, it is not migrants that drive down wages, it is bad employers that cut pay and bad governments that allow workers to be divided and undermined, and want unions to be weak and passive’."

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SNP MSP Gordon MacDonald insisted a “Tory hard Brexit” would be disastrous for Scottish jobs and the economy.

He added: "And unlike the Tories and Labour, the SNP in government will always stand up for the rights of migrants as we know how much they contribute to our economy and society.

“Scotland needs immigration – it's just a shame that the Tories and Labour refuse to see that."