To those of us who are neither French nor Francophiles, it can come as a great surprise to learn that the United Kingdom has a seat in the French National Assembly. It’s represented, as part of a wider Northern Europe constituency, by Alexandre Holroyd, a député who grew up in West London.

But then of course why would we know? It’s only French expats that get the vote. La République is one of a small number of nations that allows its citizens resident abroad to vote for their own overseas MPs.

Here in the UK, expatriates can only vote in the constituency that they were last a resident of in their home country. In 2017, overseas voting in a UK general election hit record levels, in part due to risks faced by British expats because of Brexit. Even so, only an estimated 20 per cent of eligible expats were registered to vote.

With expat political participation at such paltry levels, perhaps its time for us to consider creating our own overseas constituencies.

If we did choose, first we’d need to know how many we would need. In 2017 285,000 expats registered to vote. The average electorate of a UK constituency is about 70,424. With a bit of rounding, that means overseas voters would be entitled to four constituencies.

But, the whole point of overseas constituencies is that they are supposed to boost participation. According to Number Cruncher Politics 7.9 million eligible people are not on the electoral roll in the UK, which means about 83 per cent of people are registered to vote. If expat registration was as high as 83 per cent, then overseas voters would be entitled to 17 constituencies.

The next question is what would the boundaries of these constituencies look like? Estimates of how many British people live in each foreign country are difficult to find, and I’ve ended up using research from the IPPR from 2006 to estimate what percentage of British expats are in each country to determine how much representation in Westminster each country is entitled to. (I’ve assumed the basic distribution of Brits abroad has stayed roughly the same since then.)

For example, with 24 per cent of British expats in 2006, Australia would almost be entitled to a MP of its own if there were four overseas constituencies.

Below are possible electoral boundary maps for my four and seventeen constituency scenarios. I’ve tried to make sure each constituency has a roughly equal expat population and is geographically contiguous where possible.

Four constituencies: Europe; Australia & New Zealand; the Americas; Africa, Asia & the Caribbean.

Seventeen constituencies: Australia (x4); Spain (x2); USA (x2); Canada (x2); France, Belgium & Germany; Ireland; Rest of Europe; New Zealand; Africa; Asia; South America, the Caribbean & Middle East.

Without knowing where British expats live in countries which are entitled to more than one constituency in my latter 17 constituency scenario, I’ve taken the executive decision not to draw accurate internal boundaries – maybe they could use STV?

Now the big question: how would these constituencies vote in a UK general election? Overseas constituencies in France were the initiative of President Sarkozy, who aimed to boost participation among a group of voters who had historically tended to vote for the right.

In the UK, it is the Conservatives who have in the past extended the right of expats to vote, while the Labour party has curtailed it. The last Labour government reduced the number of years after a voter leaves the country for which they can continue to vote to 15, and the party recently opposed a private members bill sponsored by Tory MP Glyn Davies which proposed to do away with any such limit whatsoever and give expats votes for life. (To be fair, Labour is against extending the limit because of the potential administrative costs faced by local councils to facilitate this.)

Yet, since elections have been held for French overseas constituencies the right have not done as well as they might have hoped. In 2012 the Socialists won 7 out of 11 of districts, while in 2017 President Macron’s En Marche won 8 of the 11 expat districts. While higher than average income globetrotters might have once voted right, perhaps the gradual realignment of politics around the issue of globalisation means that the liberal centre-left (represented in France first by the Socialists, now by Macron, and in Britain by either Labour or the Liberal Democrats) can sweep up the expat vote. Without overseas constituencies of our own it’s hard to tell if that would be the case here.

It’s fun to draw maps though. All maps modified from Wikipedia Commons. All calculations are very rough and should be taken as loose estimates rather than proper academic research. Don’t blame CityMetric for any failures of democracy.