Since the UK voted to leave the European Union last June, the fate of the 3 million EU nationals living in Britain and the rights of 1.2 million Britons living elsewhere in Europe have become a key flashpoint of the Brexit debate, even before the Brexit negotiations officially begin.
In the coming week, Theresa May's government will try to overturn an amendment passed by the House of Lords that would automatically allow EU citizens living in the UK to remain.
A parliamentary report kept up the pressure on May on Sunday by calling for her to unilaterally guarantee the rights of EU workers in the UK.
The prime minister has been adamant she backs the right of EU citizens already in Britain to stay after Brexit – but only as part of a deal that also guarantees the rights of Britons living elsewhere in the EU.
Even if all sides were to agree to back the right of EU nationals to stay in Britain, the details of any arrangement that aims to protect the entire body of rights enjoyed today by EU nationals is far from straightforward. Here's why:
1. After two years of negotiations, there could still be no deal.
May has said she would rather get no deal than a bad deal. Ministers have been instructed to prepare for a scenario where no overall arrangement is reached.
If this happens, what would that mean for the more than 4 million people currently living in the UK and elsewhere in the EU? If this question isn’t answered soon, we may not know until 2019.
2. Many of the rights of EU nationals living abroad are guaranteed by EU citizenship laws.
Right now, every citizen of an EU member state is also an EU citizen. And an EU citizen's rights, including those associated with freedom of movement, are enshrined in EU law. EU citizenship (and freedom of movement) is the basis of many of the rights currently enjoyed by EU nationals.
Once Britain exits the EU, would UK law guarantee the exact same rights that now rely on EU rules?
Circumstances in life change over time. For example, would EU nationals be allowed to stay if they find themselves in between jobs, or would they be able to return to Britain after a period of time working elsewhere? And would the scope of the deal include students, and workers’ dependants and other family members (and their rights)?
And if there were disputes, who resolves them? All these questions are yet to be answered.
3. The principle of non-discrimination.
Within the EU there cannot be any discrimination based on nationality between workers of different member states. This means that, broadly speaking, all nationals of member states have the same priority when it comes to jobs as national workers.
It is self-evident that by leaving the EU a number of the rights and obligations that come with EU citizenship would no longer apply to the UK. It is also highly likely that in future Britain will choose to differentiate between UK and EU nationals, as it does with non-EU migrants, on a range of matters (for example, access to welfare, including in-work benefits, and to key public services, and possibly work permits).
This risks leaving the 3 million EU nationals currently in the UK (and Britons elsewhere in the EU) in limbo between existing and future systems, as well as potentially shutting the door on future job opportunities in some sectors.
4. Determining right of residence.
Another area of contention that is currently causing confusion is what will determine right of residence. Currently, providing they are not an unreasonable burden on the social assistance system of their host country, EU citizens have the right to reside anywhere in the EU.
A debate about residency is already taking place in the UK. Among those that have applied, more than a quarter of EU citizens have had their permanent residency applications rejected, including a number of people who have worked and resided in Britain for years.
Unlike most countries in Europe, the UK does not have a national ID system that would also provide comprehensive data on the number and status of EU nationals in Britain.
It is not yet known if the continued right of residence of EU nationals currently in the UK will be enshrined in a withdrawal deal or whether the British government will want this right determined through the successful completion of the 85-page residency certificate application – and if so, what happens to those whose application is rejected?
If member states push for this issue to be sorted as part of an exit deal, the residency certificate could remain – as it has been up to now for EU nationals – declarative. There is then a question of how long such an arrangement would be retained for: indefinitely or limited to a number of years? In the latter scenario, what conditions would then be applied to renewals? And would any future mechanism be reciprocated by other EU countries (the UK process would already appear to be more stringent and onerous compared to a number of other EU states)?
In a report published on Sunday, the Commons exiting-the-EU committee called on the 85-page form EU citizens are currently required to fill out to apply for permanent residency in the UK to be simplified.
5. The issue of acquired rights.
Many of the EU nationals that have worked in the UK for a number of years will have acquired a string of rights, such as access to future benefits through the country’s welfare system, and a pension. Others will be in the process of acquiring such rights. In addition to these people, there are likely to be a number of others who will have acquired rights while working in Britain in the past.
As Britain leaves the EU, the rules regulating such rights for future arrivals from the EU are likely to change. Will all rights acquired in the past be guaranteed under a different regime, whatever it may be?
This debate will be particularly tricky because member states have different and evolving social security systems, and a mechanism to coordinate between these to find a common ground of reciprocity will probably be required. As former prime minister David Cameron found during his negotiations to reform Britain’s status within the EU, this isn’t an easy task – and unlike other rights it may not be as simple as freezing the current status or grandfathering a static body of law.
Other issues pertaining to reciprocal arrangements were also raised by MPs on the exiting-the-EU committee. These include the ability for EU and UK nationals to seamlessly access healthcare in different countries on the same terms as they can now, as well as existing pensions arrangements that enable contributions in different members states to be aggregated.
6. The length of a withdrawal deal.
The UK government will at some point announce a cut-off date for EU nationals living in Britain: a specific date after which the right to stay of new arrivals will no longer be ensured. It is not yet known when this date will be.
Finally, regardless of the cutoff date, the UK and the remaining 27 EU governments will also need to decide if the terms they agree to in any withdrawal deal would be indefinite, or if they would only last for an agreed number of years.