Alastair Stewart is a freelance writer, journalist, and teacher based in Edinburgh and Almería. He regularly writes about politics, history, and culture for magazines across Europe.

I live and work in Spain and have done for the last four years. Every year, I spend three months in the UK, and the summer teaching. My family and friends are in Edinburgh and my holidays are spent there. I am and have always considered myself an economic migrant providing a service in Spain for which I am remunerated and duly taxed on.

When I left for Spain in 2014, I did so on one condition – minimal fuss. The opportunity to teach English abroad had arisen unexpectedly. I had limited Spanish proficiency and next to no knowledge of the country. It was a professional and personal gamble, and continuity of employment and negligible bureaucracy were of underlying importance.

In complete honesty, I wouldn’t have taken the punt at all if I had to worry about visas and the right to work. I was 26, had never taught before, and it would have been too much of a risk and expense. If the job wanted me, terrific – if it didn’t, I’d go home. The lack of bureaucratic ‘fluff’ made the situation infinitely easier and the rewards all the more satisfying when the whole thing worked out.

After four years, Brexit has altered this. Whatever the outcome of the negotiations it’s implausible that the paper load will remain light for much longer. Worse still, the Office for National Statistics has vanquished the myth that my case is peculiar or unique.

New data has revealed that two-thirds of the 784,900 British citizens recorded as long-term residents in the EU (excluding Ireland) are between 15 and 64 years old. For the first time, it’s been proven unequivocally that the ‘expat in the sun’ cliche is more of a myth than a stereotype.

Most ‘expats’ are in the prime of their working lives and have committed to a life abroad predicated on circumstances that are about to change. The same is true for the 3.7 million EU citizens living and working in the United Kingdom. They, too, are also living in the shadow of profound doubt and speculation as to what their lives will look like after March 29th, 2019.

There is an added dimension for both groups. Life, as they say, happens. I now have a Macedonian fiancée who also has a EU passport which has given her the right to come and join me in Spain with the same ease with which I first moved.

Compare this to her family as a warning of things to come. When both my fiancée’s parents, who only have Macedonian citizenship, wanted to come and visit us in Britain over the holiday period, they had to apply for visas. The processing time is 15 days, but three weeks before travel is advised by the Home Office. The fee is €114 per application and requires a bank statement, proof of employment or business registration and an invitation letter or hotel reservation (all need to be notarised and officially translated).

The total cost is around €150 per person, and the visitor visa is only valid for six months. In total their flights cost less, compared to my fiancée’s brother who hopped on a plane from the Netherlands and visited for a long weekend because he felt like it. The cost to him was only the flight.

Before she obtained EU citizenship, my future wife’s life in Edinburgh – where we first met – was very different. As a non-EU citizen, not only did she need to be sponsored for work, but for six years she lived in fear of what the next incumbent of the Home Office might mean for her life and professional prospects. This, of course, is to say nothing of the astronomical costs of her education at Edinburgh University compared to students from EU countries.

Fast forward to our life in Spain, and history is repeating in reverse. We want to get married and will, eventually, want to settle in the UK. Here’s the irony – while she is perfectly safe in Spain, I’m now worried about what will happen after Brexit. Conversely, while I know I can return to the UK when I please, she has to worry about whether or not she will be able to at all, irrespective of our marriage.

My fiancée could have been from any one of the other 27 countries in the EU, and the situation would be the same. The same doubt, the same fear, is happening to hundreds of thousands of families. Those British and EU citizens who migrated exercised their democratic freedom of movement at a time when the prospect of an EU referendum, never mind Brexit, was not even a talking point.

Most, if not all, of those people, have moved abroad with designs on the future. Whether they were workers, young families or retirees, they based their actions on a status quo that showed so sign of changing. From buying property to sending the kids to school, they made decisions with lasting consequences in a paradigm now about to shift.

While the UK Government calls for ‘the best deal for Britain’ it cannot guarantee a better arrangement for British or EU nationals than what we have now. As the instigating party of Brexit, the EU bloc will reciprocate with whatever treatment the British Government applies to European citizens in the UK.

In the wake of the 2016 Brexit vote, Mariano Rajoy reassured British expatriates that:

“…in the same way as Spain will defend the interests of its citizens, those British citizens resident in Spain, the millions of tourists who visit each year and the British companies established here can remain calm in this regard”.

The UK Government likewise states:

“…we want to protect the status of EU nationals already living here and the only circumstances in which that wouldn’t be possible is if British citizens’ rights in European member states were not protected in return.”

This is an oft-overlooked fact of Brexit and worth reiterating. In the run-up to the 2014 Scottish referendum, Spanish officials were widespread in their hostility to the breakup of the UK and warned Scotland that it would fall to the back of the line for EU entry. The parallels and fears about Catalonia following a similar path as Scotland, if they believed they could secure EU membership, are clear to follow.

As the Windrush scandal has demonstrated, the UK Government’s attitude to foreign nationals from outside the EU is not a kindly forbearance of what Europeans might expect after Brexit.

Reciprocation is critical, and it will be a question of who blinks first in what is now a hostage waiting game. Until then myself, my future wife, and millions of others cannot be assuaged by what ‘the best deal’ means. We must wait under the shadow of quid pro quo, and worry.