THERESA MAY’S government has long insisted that free movement of people from the European Union to Britain must end after Brexit. Commentary on this week’s Migration Advisory Committee (MAC) report has focused on its advice that Britain should not offer EU citizens preferential terms after it leaves. Yet the report pointedly adds that “preferential access to the UK labour market would be of benefit to EU citizens”. This clearly hints that a regime favouring EU migrants could be a bargaining chip to win better access to the EU’s single market.

The principle of getting free trade in return for free movement is implicit in the single market’s rules. As a matter of economics, a single market could be built around the free movement of goods, services and capital. But the EU deliberately adds free movement of people, which most citizens outside Britain see as a benefit of the club.

Yet it also permits exceptions. Harvey Redgrave of the Tony Blair Institute, a think-tank, notes that other EU countries have long been amazed that, given Britain’s hostility to EU migration, its government has never applied the constraints allowed on free movement. It was one of only three countries not to limit the migration of nationals from central and eastern European countries for the first few years after they joined the EU in 2004. Even today it is more generous than it need be. In June Britain chose not to extend limits on free movement from Croatia, which joined the EU in 2013, for two more years.

Britain is also in a minority in having no registration system for EU migrants. Post-Brexit, it could use such a system, as Belgium does, to throw out migrants who have no job after six months. Denmark and Austria limit migrants’ ability to buy homes in some places.

Most EU countries are also tougher than Britain in insisting that welfare benefits cannot be claimed until a migrant builds up some years’ worth of contributions. Equally, the EU’s posted-workers directive is used by many to try to stop any undercutting of local labour markets. But Britain is lax in enforcing both its minimum wage and its standards for working conditions.

Non-EU countries in the European Economic Area have other options. Liechtenstein, a tiny principality, has quotas on EU migrants, despite being a full member of the single market. Article 112 of the EEA treaty allows Iceland and Norway to invoke an “emergency brake”, although they have never used it. And non-EEA Switzerland, which is in the single market for goods, not only limits property purchases but also makes most employers offer jobs to Swiss nationals first.

This particular concession was secured after the EU refused to accept a Swiss vote in 2014 to set limits on free movement. Yet a further referendum on the issue is now threatened, so Brussels may have to bend its rules yet again. All this comes as other EU countries besides Britain are looking for new ways to constrain the free movement of people.

The MAC report itself points to the irony that all this is happening as EU migration to Britain is going down fast. It notes that the country may be ending free movement just as public concern about it is falling. It is not too late for a compromise in which Britain accepts something like free movement in principle, but heavily constrains it in practice.