NICOLA Sturgeon will place plans for a 50p top rate of income tax at the heart of the SNP's General Election manifesto, the Sunday Herald has learned.

SNP MPs elected on June 8 will vote to support the policy in the Commons as part of a "clear anti-austerity agenda" the party says.

Sturgeon will announce her backing for an increase in the UK-wide top rate of tax when the SNP launches its General Election manifesto on Tuesday.

The move came as Sturgeon said she remains committed to holding an independence referendum between autumn 2018 and spring 2019.

Speaking at a campaign event in Edinburgh, Sturgeon said: "My position hasn't changed and the Scottish Parliament has backed that position.

"But there is a priority now in this election and an opportunity in this election to strengthen Scotland's hand in the Brexit negotiations, because Theresa May is not just pursuing Brexit, she's pursuing an extreme form of Brexit that will put thousands of Scottish jobs on the line."

Meanwhile, Sturgeon will set out the detail of her tax policy in full at the SNP manifesto launch event in Edinburgh on Tuesday.

Sturgeon will also make clear the SNP is backing the higher tax rate for the UK as a whole.

The additional rate kicks in when taxpayers have earned £150,000 in a year. Income above that threshold is currently taxed at 45p in the pound.

Sturgeon has ruled out using new Holyrood powers to introduce the measure north of the border alone, amid fears it would place Scotland at a disadvantage with the rest of the UK.

The SNP's Stewart Hosie said the party's MPs would oppose tax cuts for the wealthiest in the next parliament.

Hosie, the SNP candidate for Dundee East, said: “In 2015 the SNP presented the only credible alternative to austerity. The Tories didn't listen and Scotland has paid the price. Working families have seen their incomes cut, public services have been squeezed, and benefits have been slashed — hitting the most vulnerable the hardest.

“A Tory victory on June 8 means even deeper cuts and further austerity. They’re gearing up to hammer the elderly, robbing them of their pensions entitlement and the cash that many need to heat their homes over winter.

“By contrast, we’ll invest to grow the economy and we won’t give tax cuts for the richest while the less well off bear the brunt. At this election the SNP will fight tooth and nail to win the trust of voters so we can stand up for Scotland against more Tory cuts.”

Meanwhile, SNP deputy leader Angus Robertson said the party's manifesto would be based on an anti-austerity prospectus.

Robertson said it was a stark alternative to the UK Tory manifesto launched by Theresa May that included plans to end universal winter fuel allowance for the elderly.

He said it would have a "clear anti-austerity agenda that would bring an end to unnecessary Tory cuts" and "tackle the projected rise in in-work poverty".

Roberston said: “Now more than ever it is vital that we have a strong group of SNP MPs who can stand up for Scotland but also represent progressive values across the UK.

“The SNP manifesto will set out a real agenda for change across the UK focussed on putting a stop to the continued public sector cuts, in-work poverty and rising inequality that the Tories are desperate to hide from.

“We will set out an alternative to unnecessary Tory austerity, back workers and families with fair pay and a fair social security system and back business with fresh support."

Robertson stressed the SNP manifesto would include a plan for how Scotland could have a "strong hand" in the UK's forthcoming Brexit negotiations.

He added: "SNP MPs will not stand by and allow the Tories to do whatever they want and get away with it - either to Scotland or the rest of the UK.

We will seek a mandate to strengthen Scotland's hands in Brexit negotiations and stand against Tory attempts to negotiate away Scotland's jobs and industries."

The SNP pledge on tax came after Scottish Tory leader Ruth Davidson used the launch of her party's manifesto last week to say that the election on June 8 was about "bringing the SNP down to size".