SHADOW Chancellor John McDonnell believes Theresa May's "completely reckless" hard Brexit plan and austerity agenda has put the Union is at risk.

McDonnell made the claim ahead of a conference he and Jeremy Corbyn are hosting in Glasgow on Saturday on Labour's alternative economic plan for Scotland.

In an interview with the Sunday Herald, McDonnell restated his opposition to a second referendum and independence, which he said would be a "huge loss" for the left and the labour movement across the UK.

However, he admitted that the Tories were making independence more likely by "alienating" people with their austerity driven policies and hard Brexit agenda.

When asked whether this was placing the Union in jeopardy, he said: "Yes absolutely, the Union is at risk."

He continued: "They [the Tories] are alienating people across the board. Of course they are being reckless.

"They are putting the Union at risk. It's absolutely chaotic."

McDonnell claimed the Prime Minister's plan to take the whole of the UK out of the single market would have devastating consequences for the economy north and south of the border.

He added: "Also, on the single market, if we don't get access to it, the economy of Scotland and the whole of the UK will sink. We've got to make sure that we're not divided.

"The Tories are being completely reckless over this issue and there is a new wave of austerity from Theresa May's government.

"This reckless wave of austerity is setting us back as is this reckless handling of Brexit."

When asked how he would respond if challenged on the independence issue at the Labour event at Glasgow's Royal Concert Hall, he said: "If I'm asked I'd say there's no need for a second referendum.

"But I'd say that Scottish independence would be a huge loss to the labour movement across the UK. We need a united working class and the loss of Scotland would be a huge loss to the labour movement.

"We need this act of solidarity at time when public services are coming under attack like never before."

The Shadow Chancellor also claimed that allowing a separate deal on Europe for Scotland would lead to resentment. He said: "I can understand the logic [of it] but I don't agree with it. I'm against a separate deal for the City of London, for Nissan and for any individual part of the UK.

"If you introduce separate deals it causes division and undermines the basis of solidarity. It causes resentment."

McDonnell went on to say the event in Glasgow, titled The Future of the Scottish Economy, would promote what he claimed could be a new "arc of prosperity" across the UK based on the redistribution of wealth.

He claimed the event would also seek to develop Labour's plans for a federal UK as an alternative to the status quo of the Union and independence. "It will give us an opportunity to open dialogue on national conversations," he said.

McDonnell also backed UK Labour's deputy leader Tom Watson in ruling out a so-called progressive alliance between Labour and the SNP to defeat the Tories at the next General Election.

He said: "I've worked in the Commons for years and if others want to support our vision that's fine, but the idea of stitching up deals before elections undermines your credibility.

"We're not going to forge any pre--election alliances."

Tory MSP Miles Briggs, in response, said: "The Scottish Conservatives are the only ones holding the SNP Government to account at a time when Jeremy Corbyn and John McDonnell destroy the Labour Party."