There is a case to be made that Tony Blair and his Home Office were the architects of Brexit. It’s an argument that stems from the choices made around the 2004 entry to the EU of the “accession eight” (A8)—the Union’s new Eastern European members.

Unlike the overwhelming majority of established EU states, the UK did not introduce any initial restrictions on the right to live and work in the country for citizens of the A8 nations—the Czech Republic, Estonia, Hungary, Latvia, Lithuania, Poland, Slovakia, and Slovenia. We treated their citizens like other EU nationals from the off.

The Home Office had predicted that the number of people moving from those nations to the UK would be less than 20,000 a year. In reality, in the first three years alone, some 250,000 people from the A8 nations came to the UK—often skilled workers providing a challenge to existing UK tradespeople. The fabled Polish plumber had arrived.

Inevitably, all this immigration wasn’t evenly spread across the country. Particular employers and sectors developed links with national communities, and the newcomers naturally often wanted to live near people they knew, or at least to get familiar food from home or something similar. Especially in the east of England, soon a particularly strong region for Ukip, some towns that had never previously seen much immigration witnessed large influxes of economic migrants.

Even though the data shows the people from A8 countries brought considerable net economic benefits to Britain, unexpected and unplanned migration has consequences: pressure for housing increased, there was more competition for school places, some people’s businesses suffered thanks to new rivals. The sense of competition for resources intensified after the economy cratered in 2007/8, and then through the long squeeze on wages and public service spending that followed the crash.

All this in turn fed into less reasonable resentments—complaints that people on the bus weren’t speaking English, and so on—and by the 2010s had propelled immigration to the top flight—and sometimes the very top spot—of polling tables about the issues voters said they cared most about.

Back in 2004, the decision not to restrict immigration from A8 countries was not, at the time, a major political issue. Not even the Conservative opposition resisted it. But the political consequences have rocked through the years since—Britain is an island at the edge of a big continent. It is not used to large-scale immigration and on recent form, doesn’t react well to it.

All this might be dismissed as a history lesson, but for one thing: the UK has every reason to expect another major influx of new, skilled migrants—this time from Hong Kong.

The UK, having now plainly failed on its 1997 promise to protect the freedoms of Hong Kong’s people after handing the region to China, has extended them an offer to move here through a new visa scheme. This is not small beer—estimates suggest around 5.4m people are eligible to move to the UK under the new programme, and where the official estimates for A8 immigration were in the low tens of thousands, this time they are much higher: suggesting 300,000 or more people could move to the UK from Hong Kong in the next few years.

The scenarios are not identical: citizens of the A8 countries were desperate to move to countries offering much better wages for the same work—and concentrated on the few EU states that were immediately open to them. Hong Kongers are not looking to emigrate for economic reasons, but political ones. But what’s similar is that at least some of them have very few options, and the UK is high on their list.

Numerous articles have been written extolling the potential benefits of this immigration—and as far as they go they are absolutely right. Around two-thirds of people in Hong Kong speak English, and it is a high-skilled workforce that could help support the government’s “Global Britain” ambitions. In economic terms, an influx from Hong Kong looks like a sure-fire winner.

The experience of the A8 wave of immigration should teach us to sound a note of caution, though. If A8 disrupted life and bred resentment among tradespeople and construction workers, large-scale immigration from Hong Kong could disrupt several high-status middle-class occupations. Unhappy professionals have a knack for making a political fuss. And just like the A8ers, Hong Kongers will likely move into a few specific cities, rather than spread uniformly. There are bound to be pressures on certain local public services and housing markets.

None of this is to say the UK has done the wrong thing, or should change course. What it does mean is that the UK could be using the time Covid-19 crisis has bought it—few people are moving continent during a pandemic—to work out how to get immigration and integration right this time.

We know that a wave of high-skilled immigration will boost the public coffers, so we shouldn’t be afraid to spend a bit of money early on—making sure councils where lots of people move from Hong Kong have extra support, so services don’t suffer. Language learning assistance, support services for integrating into a new country, and publicity measures explaining why the UK has offered sanctuary to Hong Kong’s people—emphasising the historic ties and promises made by Britain—could all help.

The government has announced a limited selection of measures, but so far has allocated just £43m to those efforts—which is less than £150 for every expected arrival, even if the official estimates are right this time. Skimping on the pennies now could cost pounds—and warp politics—later.

Councils, meanwhile, don’t even know what they don’t know. One London council, contacted by an NGO keen to make the Hong Kong visa moves a success, said it didn’t foresee any issues because it had a sizeable Chinese population already, blithely unaware that there may be tensions between groups that identify with China, and those fleeing from it.

Blair made the decision not to restrict A8 immigration because he wanted to show Britain was a forward-looking, internationalist place—and ended up throwing us sharply in the opposite direction. Let’s make sure this government’s decision to help the people of Hong Kong does not do the same again.