How Long Will It Take For The Leavers To Leave?

This piece seeks to answer a simple question: how long would it take for enough people to die that the Brexit decision would be reversed?

This has been informally speculated on before, but I haven’t seen any analysis done on the numbers, so I decided to do it myself.

The tl;dr is that the turning point is around July/August 2020:

Assumptions

To arrive at this number I had to make some assumptions:

Everyone that voted in June 2016 would vote exactly the same way again (or not vote again)
Everyone that comes of age to vote would vote in the same proportions (by age group) as in June 2016

Obviously, these assumptions don’t make a realistic prediction of the result of any second referendum, not least because the question itself would likely be different.

The Numbers

To arrive at the number, I first took the raw votes from June 2016:

Leave: 17,410,742
Remain: 16,141,241

Then I got the breakdown of votes by age group, based on the figures from Lord Ashcroft’s site here:

LeaveRemain18-240.270.7325-340.380.6235-440.520.4845-540.560.4455-640.570.4365+0.600.40

From here, what we need to work out is:

How many people will come ‘of age’ to vote per month
How many people will die per month, by age group

Fortunately the ONS collects data on births and deaths by age group, so we can estimate these values.

How Many New Remainers Will There Be?

These are the population figures broken down by age group at the time of the 2016 vote, taken from ‘ukmidyearestimates.xls 2012-2016, UK population counts for mid 2016’.

0-440143005-9403750010-14362510015-19377890020-24425380025-29451060030-34440820035-39417950040-44417410045-49461910050-54463200055-59406670060-64353420065-69363650070-74285210075-79215450080-84160670085-8999300090 and over57120065648000

Unfortunately the age groups do not align with Lord Ashcroft’s figures in the first table, but we can estimate the number of people who get the vote every month by taking the number of people in the 15-19 age group (3778900), and multiplying them by 3/5ths to get the number of people who could not vote in 2016 that can three years later.

This gives us a number of 2267340. Over the three years, this is 62982 people per month that can vote.

If we assume that the proportions voting for either side remain the same for the 18-24 age group, then 46% more of these votes will go to remain than leave (73% – 27%).

This gives us a final figure of 18,754 extra remain votes per month.

How Many Leavers Die Per Month?

Deaths by age group vary little over the years, so I took the numbers recorded in 2016, 2017 and 2018:

201615-441512845-6462,67965+442,767201715-441451445-6462,51765+452,329201815-441514045-6463,91365+456,731

Looking at these numbers gives roughly 450,000 people in the 65+ age bracket dying per year. Deaths between 15-64 are relatively speaking negligible, and the voting proportions by age group mean that votes lost and gained roughly cancel one another out (the exact numbers give a few dozen more to remain per month, but this can be ignored).

Dividing 450,000 by 12 gives a figure of 37,500 deaths per month in the 65% age group.

Taking the net leave vote in that age group (20%) and multiplying out gives a figure of roughly 7,500 leave votes lost per month.

Taking the net of the two numbers gives a gain for leave votes of about 26,000 per month, resulting in this graph:

which gives a rough crossover point of mid-2020.

Conclusion

I’ve made many crude assumptions here, and one could argue on both sides for tweaks to the numbers here and there. For example, you could argue that those in the 15-18 age bracket in 2016 would be even more likely to vote remain than the 18-24 cohort.

And of course, this analysis makes assumptions that won’t hold true in reality, such as that everyone would vote the same way as in 2016, and the age group analysis of voting patterns was accurate and uniform within the groups.

Broadly, though, the demographics point to a majority for remain happening around mid-2020 if nothing else changed from 2016.