A few months ago, Britain’s most senior ambassadors gathered in the Foreign Office to compare notes on Brexit. There was one problem in particular that they did not know how to confront. As one ambassador put it, the English--language publications in their cities (it would be rude to name them) had become rabidly anti-Brexit: keen to portray a country having a nervous and economic breakdown. Their boss, the Foreign Secretary, later summed it up: many believe that Brexit was the whole country flicking a V-sign from the white cliffs of Dover. The job of his ambassadors is to correct this awful image. But how?

Their plight has not been made much easier by the Prime Minister. Last year she gave two good speeches, in Florence and at Lancaster House, about how Britain is ready to make new allies and go global. Fine words, but they come all too rarely and, anyway, a government is judged on what it does rather than what it says. To those in the Windrush generation fearing a knock on the door from immigration police or to Czech nurses still waiting to be told if they can stay after Brexit, it will seem that a theme is emerging. That the Prime Minister’s real agenda is not to go global, but to raise the drawbridge as her country turns in on itself.

This week ought to have provided the perfect chance to cast off this image. The Commonwealth summit has been a celebration of how empire gave way to a fraternity of 53 nations, 16 of which still choose to have the Queen as head of state. The streets of Westminster have filled with delegates, many in national dress. A wonderful sight. But the newspapers they carried had news of how citizens from the Commonwealth, invited to Britain decades ago, are now being investigated and deported. They have been asked to provide residence records, some of which the Home Office has itself destroyed. Behind each statistic lies an awful story.

Like, for example, that of Paulette Wilson, who used to work as a cook in the House of Commons. Aged 61, she was sent to a detention centre prior to deportation to Jamaica — a country she had not laid eyes on since childhood. She was asked for residence records, and had not been saving them because she never imagined she’d need them.

Or Michael Braithwaite, who lost his job as a special needs teaching assistant when the Home Office deemed him to be an illegal immigrant. He had lived in Britain for half a century. And these are just some of the cases we know about — brought to light only due to outstanding reporting by the Guardian.

The government says it cannot say how many have been deported, as it would cost too much to count them all. This is what it looks like when bureaucracy trumps humanity.

Mrs May’s apology (which came after her initial refusal to meet Commonwealth leaders) was embarrassing. But at a time when the world is still trying to work out what direction Britain is taking, it is also damaging. And it fits a trend. The 3.7 million EU nationals in Britain have found themselves victims of the same Home Office intransigence — a mindset that is an indictment of the culture Mrs May once presided over. Even now, their status (whether they can stay, retire, be treated on the NHS and receive a state pension) has not been assured because the Prime Minister seeks to use them as bargaining chips, waiting for reciprocal assurance from the EU about British nationals.

There is a clear logic to her strategy, but it’s also the kind of cold logic that ended up in deportees being advised to adopt Jamaican accents to fit in with where they were headed.

Placing EU nationals in immigration purgatory was Mrs May’s personal idea. Every Brexit campaigner and all of her rival candidates in the Tory leadership race wanted to grant immediate and unconditional guarantees that they would not be affected. But Mrs May has always prided herself on her firmness as her selling point. Even now, she privately complains that her whole cabinet is wet on immigration apart from Gavin Williamson, the defence secretary, and Karen Bradley, the Northern Ireland Secretary (and her protégée).

You can argue that Britain is one of the most welcoming countries on earth, that we have taken in 17 EU nationals for every ten who have left since the Brexit vote. But this is of little comfort to those who feel that Britain is now a less welcoming place. Last week, I met Swedish business leaders who say their colleagues in Britain are hearing anti-immigrant comments for the first time. This can’t be dismissed as oversensitivity: what matters is that enough people believe it to be true. When the Home Secretary floats bizarre ideas such as employers keeping registers of foreign workers, no wonder they worry.

The Home Secretary in question is Amber Rudd, a leading light in the Remain campaign (and, by the end, its de facto leader). It’s impossible to accuse of her of being anti-immigrant. So why would she even consider asking employers to make an immigrant register? When Tory MPs were discussing the Windrush debacle in their WhatsApp group, it tended to be the Remain--voting MPs defending the government and the Brexit-eers who were most aghast.

There are theories about this inside Westminster: that those wanting Britain to leave the European Union were painfully aware that they’d be accused of xenophobia, so would go to great lengths and make great gestures to answer these claims. (Boris Johnson’s plan for a bridge to France is one such example.) But many Remainers genuinely believed they were engaged in a battle of ‘open’ vs ‘closed’ — and that ‘closed’ won. So as democrats, they ought to obey what they believe to be the demand of Brexit voters: clamping down on migration, sounding more tough and less liberal.

This is a tragic misreading not only of the referendum result, but of public opinion today. Seeking to control immigration is not the same thing as being anti-immigrant: now that control is assured, support for immigration has risen sharply. A poll last year showed that 71 per cent of Leave voters would back a system that controls low-skilled migration from the EU with no limit on high-skilled newcomers. This rises to 75 per cent among Conservatives. Just 14 per cent of the public disagree with this idea. It is the obvious next step.

Such a policy should replace the current crude immigration target, which has not been met since it was created. Mrs May once referred to the target as a ‘comment’ during last year’s campaign, which was truer than she would admit. The policy was created on a television studio sofa by Damian Green, Mrs May’s erstwhile deputy, who said during a TV interview that the Tories would cut net migration to the ‘tens of thousands’. This was not an agreed policy. Rather than admit that the (then) immigration spokesman had misspoken, the Tories turned his slip of the tongue into policy. So the ‘tens of thousands’ pledge remains to this day, supported by almost no one in cabinet.

Chasing this target has led to the Windrush debacle and more madness. Migration from the EU cannot be restricted until we leave, so all of the pain is focused on those from outside. If the Home Office cannot deport professional beggars from Romania, it goes after law-abiding Brits who have been living here for decades but are unable to provide proof of their status. We also insist that if a UK national marries someone from outside Europe, they cannot live with them unless they earn £18,600 a year. This heartless stricture resulted in Irene Clennell — a wife, mother and grandmother — being deported to Singapore after living in the UK for 30 years. Why? Because her British husband was unable to work after suffering a hernia.

A more effective Labour party leader would have had plenty to say about how the Windrush scandal exposes the dark heart of Conservatism and a party that sees numbers, not people. The truth is that this exposes a dysfunctional form of Toryism and a party hierarchy that still fails to understand the true motives of Brexit supporters and the opportunities it will present.

After Brexit, the government will be able to control all immigration, so it can start talking now about a better and more liberal system. The object should be to win the global war for talent. Limits should be placed on unskilled labour, as is common in most countries, but skilled workers should be welcomed with open arms. There should be no more treating Australians or Indians as second--class immigrants, and no more violinists deported to Massachusetts because they don’t earn enough. Plans can be made to abolish the worst defects of the current system.

Our world-class universities (we have six in the global top 30 while no other EU country has any) should be allowed to recruit as many overseas students as they can manage. Those who graduate with a proper degree should be welcome to stay for a further five years. And, if they settle down, invited to apply for full citizenship. There ought to be hundreds of state-funded scholarships, offered globally, to underline Britain’s intent about strengthening its wider networks. There need be no delay in removing students from the immigration quotas.

And if Britain has a skills shortage, more can be done to meet it by training the low-skilled. We need a new breed of schools specialising in STEM skills and putting as much effort into steering pupils towards an engineering apprenticeship at Rolls-Royce as today’s top schools expend on getting them a PPE place at Balliol. It will cost, but there are plenty of savings to be made from the failed apprenticeship levy system. Savings from the EU membership bill are also on their way: the Office for Budget Responsibility estimates the cost (currently £8.6 billion a year) will be below £1 billion within seven years.

These are not unachievable ideas, and nor are they without Tory champions. They would sit well with the free-trade agenda which will be the bedrock of post-Brexit ambitions. Almost every member of the cabinet would abolish the immigration target in a heartbeat. Jo Johnson was so passionate an advocate for higher education reform that he was sacked as universities minister to give No. 10 a quieter life. The Conservative party has no shortage of people with ideas about a liberal Brexit or how to achieve it. But until now, they have kept quiet so as not to destabilise their leader at a difficult time in negotiations.

They are not doing her any favours. Mrs May is no xenophobe but she is using Iron Lady tactics at a time when warmth, accommodation and communication are needed. When she first entered No. 10, she was teased for saying that ‘Brexit means Brexit’. Almost two years on, she is still struggling to improve on this definition. In the absence of any government ideas, Brexit will be defined by its enemies — and her blunders.

As Prime Minister, Mrs May has two big battles on her hands: to negotiate a deal with Brussels then win the battle for Britain’s global reputation. It’s about time that she started to fight.

The party hierarchy still fails to understand the true motives of Brexit supporters

Spectator.co.uk/podcast Fraser Nelson and Chris Wilkins on Brexit battles.