BREXIT will be so damaging for the UK that it will try to rejoin the European Union within a generation, the SNP’s Brexit minister has predicted.

Michael Russell told MSPs there was a “high chance” the coming Brexit negotiations would fail, and the Scottish Government was working on contingency plans in case they did.

He said any collapse would “probably happen sooner rather than later”, with the EU’s demand for a “divorce bill” of between £50 billion and £85bn from the UK the most likely cause.

The Tories accused him of an “hysterical outburst”.

Theresa May recently restated her willingness to quit the talks with the other 27 EU nations, saying “no deal is better than a bad deal”.

That could mean the UK falling back on bare-bones World Trade Organisation rules and the introduction of tariff barriers with Europe.

Giving evidence to Holyrood’s European and External Affairs Committee, Mr Russell said: “I think the chances of the UK not sticking with the negotiations are high. I don’t think they are necessarily 50 or 60 per cent but they are high … We would have to be prepared in those circumstances. We have a range of scenarios that we look regularly.

“You start probably with that issue and you work your way through hard Brexit with detriment to devolution, hard Brexit without detriment to devolution, moderate Brexit in which devolved powers are increased, through to independence, of course, which we believe is the offering that should be made.

“So we look at all of those and we have thought through some of the issues. But if there’s going to be a collapse in negotiations it will probably happen sooner rather than later.”

Mr Russell said EU leaders were “mystified and troubled” by the UK’s decision to leave, but wouldn’t be “hectored and pressured” by Mrs May, as they had their own priorities to consider.

He said: “There are bigger issues. I actually think in 20 years – if the UK does come out – the UK will be in the process of trying to be back in.

“And it will have lost 20 years of influence and 20 years of progress and 20 years of prosperity.”

Tory constitution spokesman Adam Tomkins said: “Mike Russell’s hysterical outburst gave the impression that he would love nothing more than for the UK to fail in these talks.

“For a minister in Nicola Sturgeon’s government to be willing Theresa May’s negotiations to collapse is an utter disgrace.

“What Scots want is for the SNP Government to get behind Britain’s negotiations with the EU, not to seek constantly to undermine them.”

In other election developments: l Jeremy Corbyn announced Labour’s draft manifesto, which had been leaked in its entirety to the media, had been unanimously approved and would be published “in the next few days”.

l The manifesto promises state-owned rail and energy services and higher taxes on the rich.

l Mrs May called the leak indicative of the “pretty shambolic” state of the Labour Party.

l Gordon Brown rallied Labour activists in Coventry – but failed to mention Mr Corbyn.

l A BBC cameraman’s foot was run over Mr Corbyn’s car.

l LibDem leader Tim Farron said the UK had failed to “do the right thing” for Syrian refugees.

Nicola Sturgeon claimed Mrs May was already “poisoning the well” of the Brexit talks by using the fate of EU nationals in the UK as bargaining chips.

Campaigning in St Andrews, in Fife North East, with candidate Stephen Gethins, the SNP’s Europe spokesman, Ms Sturgeon said: “EU citizens enrich Scotland’s cultural fabric and boost our economy - and frankly our public services could not function without their vital contribution.

“It is utterly contemptible that the Tories continue to use human beings as a bargaining chip in Brexit negotiations – and in doing so they are poisoning the well before talks have even begun.

She warned universities like St Andrews would also be harmed by a hard Brexit.

On a visit to the Western Isles today, Scottish Labour leader Kezia Dugdale will say unique Scottish exports, such as Stornoway black pudding, must be protected after Brexit.

She said: “Food and drink exports are a key part of the Scottish economy, particularly our island economies. They secure jobs, grow the economy and are essential to the distinctive nature of Scotland’s Highlands and Islands. “Any post-Brexit trade deal must protect the status of our key food and drink products.

“The Tories would sell our islands’ economies down the river.”

The UK Government last month rejected Nicola Sturgeon’s plan for a bespoke Scottish Brexit, in which Scotland remained in the EU single market, as unworkable.

Ms Sturgeon says she wants Scots to vote in a second referendum by spring 2019 to choose between Brexit and the UK or a more pro-European independence.

However the Prime Minister has refused to agree, saying “now is not the time” given the UK’s focus on Brexit.