THE revelation that Britain has not, after all, been over-run by bogus students or benefit tourists is the latest devastating blow to the intellectual case for Brexit. OK: perhaps intellect has never had much to do with the case for leaving the European Union, which seemed to have been largely motivated by an irrational fear of foreigners. But the chaos of the British Government’s position is daily more evident. This is now turning into a national humiliation

None of the original arguments for Brexit have withstood the test of time: from the fictitious £350m for the NHS, to the nonsense about the European Court of Justice dictating the law in British courts. From the delusional forecasts of non-EU trade, to the reality of immigration statistics, the Brexit project is in ruins. The whole exercise now appears to have been based on a collective suspension of disbelief, a consensual con.

Until last week, the UK Government falsely claimed that nearly a 100,000 students were remaining in Britain, many illegally, after graduation. It turns out that 97 per cent actually return home, according to the Office of National Statistics, and only around 4,600 hang around in the UK. It's much the same with people on work and visitor visas. The Home Office has discovered, to its amazement, that visitors to Britain invariably return home when they are expected to.

The Government has also had to concede that benefit tourism is a Brexit myth. Less than 2 per cent of UK tax credits go to migrants from Europe. Immigrant workers contribute around £7bn more in taxes than they cost in terms of benefits. Migrants do not steal the jobs of British workers or significantly depress wages. The current immigration squeeze is likely to cost the UK exchequer £6bn a year by 2021 according to the Office of Budget Responsibility.

Why on earth didn’t someone check all this before June 2016? Apart from the reputational damage to the UK from this demonisation of hard-working visitors, the Government has inflicted needless damage on one of Britain’s great success stories: higher education. The 350,000 international students in the UK are worth around £10bn to the UK economy, according to Universities UK. Yet the British Government has been trying to cut the numbers studying in Britain by half – yes half – because it believed wrongly that this was a major portal for illegal immigration. Tighter visa restrictions led to 27,000 fewer international students arriving in the UK last year. But at what cost? The immigration authorities introduced demeaning bureaucratic checks on income and family circumstances of international students – treating these valuable people, future leaders of business and politics, as human refuse.

This has been a disaster for Scotland, which has no fewer than 10 universities among the world's top 200 destinations for non-UK students. Edinburgh University used to hold Namaste evenings to welcome Indian students and staff coming to work and study here. I was told recently that these had lapsed because Indian students aren't coming any more. They are going to Canada or Australia where they face fewer visa restrictions than in Britain. A country which in living memory had a White Australia policy is seen as more welcoming than the UK.

There are three million EU nationals in Britain contributing to the wealth of the country. They have been maligned by a government that preferred to believe the exaggerated estimates made by anti-immigrant groups and the tabloid press rather than find out what was actually happening at Britain's borders. Only now are proper checks being made of people entering and leaving the UK. This is a dereliction of duty that has had profound consequences for the future of all of us in Britain, but especially for Scotland, which requires something like 24,000 migrants a year just to stand still demographically.

Unscrupulous politicians and an irresponsible press suggested that hordes of EU migrants were coming to Britain because of free movement. “Britain is full up”, said Migration Watch. Gordon Brown, the former Labour Prime Minister, got in on the act, promising “British jobs for British workers” in 2008. The threat to British “culture” from “uncontrolled" immigration was even discussed on liberal programmes like Newsnight.

Yet the reality is that Britain has always had powers, even within the European Union, to restrict immigration if it really wanted to. EU citizens only have a right to come to Britain and look for work for three months. After that they must prove they have a job, are in full-time study or are wealthy enough to support themselves without relying on the benefit system, or they can be deported.

If Britain had had reliable statistics on immigration, and if the Government had explained that free movement does not mean benefit tourism, then it is most unlikely that the country would have voted as it did in the EU Referendum in 2016. Add to that the emerging economic realities: the collapse of the pound, the slump in manufacturing (British growth is now half that of the European Union) and the continuing pay squeeze, and there would have likely been a landslide for Remain. Indeed, it might have been more like Scotland, where all political parties reject the demonisation of migrants, and where people voted to remain in the EU by a margin of two to one.

Imperial fantasists in the UK Government allied with racially-motivated populists to portray the EU as a migration machine that was bent on turning Britain into a foreign country. Students, teachers, nurses, doctors, businesspeople and agricultural workers were cast almost as an invading army being sent to extinguish Britain's national identity. Meanwhile evil bureaucrats were conspiring, we were told, to overwhelm Westminster with EU legislation, backed by the European Court of Justice. This has now been exposed as paranoid nonsense. The UK government had to admit in the Brexit White Paper in January that, far from losing our independence to Brussels, Britain “remained sovereign throughout our membership of the EU”.

Since negotiations on withdrawal began, Brexit fantasists have had a crash course in international law. They've discovered what most of us knew all along, that in order to retain access to Britain's largest export market – the EU – Britain is going to have to accept most of the rules of the single market, and the opinions of the European Court. Last week, the Foreign Secretary, Boris Johnson, finally conceded that Britain will have to pay the “divorce bill” despite having said in Parliament that Brussels could “whistle for it”.

The Government is now finally conceding that, after Brexit, Britain will still need immigration as it does today. Much of our industry depends on migrants, as do the agricultural sector, the National Health Service and social care. A consensus is emerging among farmers, the Confederation of British Industry, devolved governments and even sections of the British civil service, that Britain simply cannot afford to lose access to European labour or to European markets.

The gears are crashing into reverse all across the British Establishment. The reality is that Britain will remain, to all intents and purposes, part of Europe, but will have no say on the rules that govern it. Baseless fears about migration from the EU have been responsible for an epic act of national self-harm. This entire generation of British politicians stands accused of perpetrating what future historians will judge amounts to a fraud on the British people.