NICOLA Sturgeon is to accuse the Tories of planning a “double hit on Scottish families” .

As the First Minister moves to focus the General Election campaign on to the economy, she will say in a speech tomorrow that Theresa May plans to hit poorest families with tax hikes and an unprecedented level of austerity.

Hitting back last night Scottish Tory finance spokesperson Murdo Fraser, said: “This biggest threat to prosperity in Scotland is not from a Conservative government, but from Nicola Sturgeon’s obsession with cutting us off from our biggest market, the rest of the UK.”

Speaking at the Scottish Trades Union Congress, Sturgeon will put the economy front and centre by attacking the Tories in the wake of mounting speculation that the party is set to increase tax and scrap the ‘triple-lock guarantee’ protecting pensions.

She will warn that an emboldened and re-elected Tory party would mean the UK’s welfare state facing the greatest threat since its inception after the Second World War.

“With a large majority of hard-line Tories our social security system that so many depend upon will never have been in greater danger”, Sturgeon will say at the annual STUC conference in Aviemore.

The First Minister will say, in her first significant speech since the General Election was called for June 8, that the “price of voting Tory at this election has never been higher”, as Theresa May was accused of planning to hammer working class families with tax rises and welfare cuts.

May remained under pressure this weekend over reports that workers will face a tax increase after Chancellor Philip Hammond said there should be “flexibility to manage the system” of taxation.

However, the Prime Minister insisted yesterday the Tories are “a lower tax party”, as she faced questions over speculation they may raise taxes if they win the General Election. Speaking at the campaign event in Dudley, in the West Midlands, May, however, would not say whether she would keep her party’s 2015 manifesto pledge of no rises in VAT, national insurance or income tax.

May is also facing calls to spell out her plans for pensions, after she failed to commit the Tories to preserving the triple lock guarantee. Under the triple lock the state pension increases each year by whichever is higher: inflation, the increase in average earnings or 2.5 per cent.

Last night the SNP said May’s interventions laid bare an “increasingly right-wing Tory party who refuse to give honest answers about such key issues as pensions, taxes and the true impact of a Tory hard Brexit”.

Sturgeon will claim that Brexit-obsessed “hardliners” in the Tory party will ensure that “those least able to pay” will suffer the biggest burden of higher taxes and austerity.

“We are at the start of an election campaign where competing visions will be put before the people – and one of those visions, the Tory vision, should be ringing alarm bells loud and clear across Scotland,” she will warn.

“The hard-liners have taken over the Tory Party. And now the Tory hard-liners want to take over the country. Scotland knows there has always been a cost to voting Conservative – but the price of voting Tory at this election has never been higher. And it will be those least able to pay that price who will bear the biggest burden. The Tories will impose a double hit on Scottish families and communities: A poorer country. And a more unfair, unequal society.”

Sturgeon will also maintain that a decisive Tory victory will usher in a new era of Thatcherism which would hurt the working class.

“We already know Brexit will hit wages and jobs. The UK Treasury itself said Brexit will leave the UK “permanently poorer’. But now the Tories are threatening to walk away from Europe entirely and, in their words, ‘change our economic model,’ she will say.

“A changed model is precisely what the former Chancellor, Lord Lawson, had in mind when he said: ‘Brexit gives us the opportunity...to finish the job that Margaret Thatcher started’. The truth is the Tories are starting to think they can do anything to Scotland and get away with it – and that means it has never been more important for people across Scotland to think clearly and ask themselves this question: ‘How can we best protect Scotland from the hard-line Tories?’”

Sturgeon’s speech followed the First Minister ruling out any SNP-Tory coalitions at a local level after the council election on May 4.

STUC General Secretary Grahame Smith also warned that the Tories' tax plans would “cut the living standards of ordinary workers” and “depress economic demand and hit jobs”. He said: “They will allow wealthy individuals and corporations to continue to avoid paying their fair share.”

Scottish Green co-convenor Patrick Harvie said any tax increases “will hit people on ordinary incomes who are already struggling with the Brexit price rises”.

Scottish Labour’s General Election campaign manager James Kelly, echoing the criticism, said: “Since 2010 the Tories have given tax breaks to those at the top while working people have been hit with VAT rises and cuts to in work support.”

MEANWHILE Scottish Labour will have its candidates in place within days, party leader Kezia Dugdale has confirmed

Dugdale will lead a selection panel that includes six other members to pick candidates after the party said it had received around 150 applications.

The move came ahead of a visit to Scotland tomorrow by Scottish Labour leader Jeremy Corbyn. He is due to make his first appearance north of the Border since the General Election was called.

He will also deliver a speech at the Scottish Trades Union Congress in Aviemore on the same day Nicola Sturgeon is due to speak to the annual event.

Corbyn will also visit Dunfermline, where he will appear alongside Dugdale at a campaign event.