The National:

JUST over three months since Great Britain left the European Union's single market and customs union the scale of the impact of this act of national self-harm has been huge, not least in Scotland where many companies are struggling to survive. This is an economic drama documented on a daily basis in the media.

Less visible but equally damaging and, in the longer run, probably even more so is the rising exodus of EU nationals from Britain, including Scotland, both before and since freedom of movement ended on December 31 last year. Scotland's future as a young, vibrant, open society is at risk. Its population could not only get older but smaller.

The latest (June 2020) estimate for the number of EU nationals living here, according to National Records of Scotland, was 231,000 or 56% of all 409,000 non-British nationals living in Scotland.

Analysts such as Professor Jonathan Portes of King's College, London, suggest that over a million EU nationals have left the UK in recent years, with around 700,000 of these abandoning what were well-paid jobs in London. These figures are surrounded by uncertainties, with the Office of National Statistics pointing to an exit of under 200,000 while Madeleine Sumption, head of the Migration Observatory in Oxford, says it could be 450,000 or, then again, 300,000. And, as yet there is no reliable figure for Scotland on its own. (We may have to wait for Census Day 2022).

But we know from anecdotal evidence at the very least that people are leaving even though Scotland has demonstrably offered a far less "hostile environment" than, say, parts of England. One reason cited by EU nationals is the bureaucratic process of acquiring pre-settled and settled status. Another undoubtedly is an increase in outright racist abuse.

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There's also evidence that the enormous economic hit suffered by the UK economy because of the Covid-19 pandemic and Brexit – a decline of almost 10% in 2020 – is far greater than that experienced in EU nationals' home countries. The dream of a better life that was so tempting in, say, 2005 or 2010 has evaporated.

The coronavirus crisis has ended that dream for many, often low-skilled, working in tourism, agriculture, manufacturing and administrative and support services, not forgetting health and social care – sectors identified by the Scottish Government as attracting young EU nationals. The government here, after drawing up two scenarios – an 80% cut in EU net migration and one of 50% – suggests that annual overseas net migration to Scotland could decline by between a third and a half after 2020.

That, in turn, could mean that the population growth we have witnessed in recent years is or could be over. The number of people living in Scotland grew from 5.07m to 5.42m between 2000 and 2017 and, had we stayed in the EU, was set to reach 5.85m in 2041 (Portes) or 5.6m in the same timeframe (Prof Graeme Roy, now of Glasgow University). It might now fall to 5.3m or lower.

The impact of this declining population could be significant, perhaps devastating. EU nationals tend to be younger and more likely to be employed than the indigenous population, so add to the country's tax yield (already suffering from the disproportionate Covid-19 hit to the Scottish economy and likely to decline further if parts of the active labour force move away.) And this at a time when the Scottish Government admits that the proportion of those aged over 65 will rise from 29% to as high as 46% over the next 25 years.

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It's hardly surprising then that Scottish ministers have been arguing, albeit forlornly so far, for immigration policy to be devolved and for freedom of movement to be restored. “We need to keep attracting people to Scotland, and to keep providing opportunities for people born here, in order to grow our economy, provide staffing for our public services and to raise the tax revenue needed for the NHS and other services,” Nicola Sturgeon said in her St Andrews's Day address of 2019.

These policies are the sine qua non of preventing that drift to a more closed, older and, probably, poorer country all parties and candidates in the current election campaign should fear.

David Gow is co-editor of sceptical.scot, senior adviser to Social Europe and former European Business Editor of The Guardian in Brussels