Image copyright PA

A leaked UK government analysis of the impact of Brexit on the country's economy has been described as "devastating" by Nicola Sturgeon.

The documents said growth over the next 15 years could be up to 8% lower than if the UK stayed in the EU.

Scotland's first minister said the analysis vindicated research already published by the Scottish government.

And she said the case for a so-called hard Brexit was now "dead in the water".

The document, which was obtained by Buzzfeed, is said to look at the likely impact of different scenarios for the UK's future trading relationships after Brexit.

It concluded that UK economic growth would be slower outside the European Union, no matter what deal is ultimately struck with Brussels.

UK government ministers have sought to play down the significance of the analysis.

Responding to an urgent question in the Commons, Brexit minister Steve Baker told MPs the document was at a "preliminary" stage and "requires further work".

He described the document as a "preliminary attempt to improve on the flawed analysis around the EU referendum" and said it did not asses the government's preferred option of a bespoke free trade deal.

And he said there was "clearly" a campaign to overturn the 2016 EU referendum by some people in the media and the House of Commons.

'Accused us of scaremongering'

Ms Sturgeon said the "devastating leak" was a watershed moment in the Brexit negotiations - and again underlined the importance of single market and customs union membership.

The first minister added: "For months, Theresa May's government have refused to produce any detailed analysis of the potential impact of various Brexit scenarios - now we know why they have so desperately engaged in a cover-up.

"When the Scottish government published our own impartial analysis a few weeks ago, showing an extreme Brexit could cost each person in Scotland £2,300 a year, the Tories accused us of scaremongering.

"Now we find out that behind the scenes they agreed with us."

Image copyright Getty Images Image caption The Scottish government published its own analysis of the economic impact of Brexit earlier this month

The Scottish government analysis, which was published on 15 January, said Scotland's economy would be £12.7bn a year worse off under a so-called hard Brexit.

At the time, the Scottish Conservatives dismissed the analysis as "completely over-the-top scaremongering".

Ms Sturgeon called on the prime minister to now publish the leaked analysis in full, along with "any other analyses which they are concealing from the people of these islands".

And she urged Mrs May to "face down the hard Brexiteers around her - and put jobs and living standards front and centre of the Brexit negotiations by remaining in the single market and customs union."

What does the leaked Brexit document say?

According to Buzzfeed, the leaked document, entitled EU Exit Analysis - Cross Whitehall Briefing and drawn up for the Department for Exiting the EU, suggests almost every part of the economy would suffer.

It suggests UK economic growth would be 8% lower than current forecasts, in the years ahead, if the country left the bloc with no deal and reverted to World Trade Organisation rules.

It says growth would be 5% lower if Britain negotiated a free trade deal and 2% lower even if the UK were to continue to adhere to the rules of the single market.

But Conservative MP and leave campaigner Iain Duncan Smith told the Today programme the paper should be taken "with a pinch of salt" as almost every single forecast on Brexit has been wrong.

"It's an incomplete report... deliberately leaked because it gives a bad view," he said.

And government sources point out that the document has not modelled the effect of a bespoke deal covering trade and financial services - the government's preferred scenario - and it does not attempt to anticipate the outcome of negotiations.