Constitution Secretary Angus Robertson will today reiterate that rejoining the EU offers a route to Scotland’s growth and prosperity, despite data showing the UK is its biggest trading partner.

In the latest paper arguing the case for independence, Mr Robertson is expected to ignore the importance of its historic trading ties with the rest of the UK which he will blame for driving down Scotland’s living standards.

Instead he will say the success of independent EU countries demonstrate the “immense value of being part of the world’s largest single market”, which is seven times larger than the UK.

Critics point out that this does not translate to seven times more business and that the UK still accounts for 60% of Scotland’s total trade.

Ahead of launching the latest paper in the Building a New Scotland series which is updating the independence prospectus, Mr Robertson said: “Independent EU countries like Scotland are wealthier and fairer than the UK, so with all our resources and talents why not Scotland?

“People in Scotland voted overwhelmingly to remain in the EU but as on so many other occasions our views have been ignored by Westminster.

“Both Labour and the Tories are happy to impose a disastrous hard Brexit on Scotland which the UK Government’s own fiscal watchdog thinks will cut national income by 4% compared with EU membership – wiping around £100 billion from the UK economy and leaving people on average earnings £1,300 a year worse off.

“Today the Scottish Government is setting out an alternative direction for Scotland which will detail our shared European values, how we will trade with the rest of the UK and the EU, the immense value to Scotland of being a European Union member state and the contribution we would make to achieving the EU’s goals.

“There will of course be challenges, and the tried and tested accession process to go through, but we can escape the costs of Brexit and build a new and better relationship with our friends on these islands: taking advantage of new opportunities as part of the EU and the world’s largest single market, which is seven times the size of the UK.”

Pamela Nash, chief executive of the anti-separation Scotland in Union campaign, said: “If this document is to have any credibility whatsoever, it needs to answer key questions about a separate Scotland joining the EU – including how border controls would work, when the new Scottish currency would be replaced with the euro, how public spending would be reduced, and what impact leaving the UK internal market would have on jobs and livelihoods.

“If it fails to be honest with voters and answer these questions and many more, then this must be the very last time the SNP wastes public money on its constitutional obsession”.