Back in the old non-stockpiling days I used to write a lot about our electoral system. I blamed it for many of our political ills. It is fair to say that on occasion I have gone a little over the top in this pursuit: I’ve got form.

But this time I really think I am onto something: First Past the Post has made Brexit more toxic.

Firstly let’s look at the EU referendum vote itself: a binary choice on a highly simplistic question. For decades, most of the elections people voted in used a system where often their vote did not really count. Live in a safe Tory seat? Your vote doesn’t matter. Live in a safe Labour seat? Ditto.

Suddenly, here was a choice that actually really did matter and every vote was going to count. Voters were finally able to exercise their vote to administer a kicking. What better opportunity to hit politicians where it hurts – and potentially in the case of Cameron and Osborne drive them out of Downing Street.

This temptation proved too much for some. I know some who voted Leave simply because Cameron supported Remain. There were plenty of other non-EU related reasons people voted Leave, too. This is the big danger of referendums, that voters not politicians ultimately choose the question to answer – and under First Past the Post, this is magnified because most voters don’t see their vote count.

Secondly, we need to consider why we had a referendum in the first place. We have a representative democracy in this country: we elect MPs, and they go to Westminster to make decisions on our behalf. If, after a few years we think they’ve done a good job, we might give them another go – or we might kick them out.

So why could the EU issue not be settled this way? The answer to this is complicated but can be boiled down to three main points. MPs as a collective had become detached from what voters thought about the EU. A lot of voters were sceptical, but the vast majority of MPs and the main political parties were in favour of remaining.

Ukip were formed in response to this, and attempted to get MPs elected in order to have representation of this widely held viewpoint in parliament but the system worked heavily against them. In 2015, Ukip got 12.6 per cent of the vote but less than 0.2 per cent of the seats. This allowed pressure to build up as millions of voters had very little representation for their views in parliament.

Ukip exerted extreme pressure regarding this issue on a Conservative Party that was split down the middle. Ukip were a threat to the party retaining power under First Past the Post – and Cameron felt he had to offer a referendum to quell the threat. So our electoral system prevented a mainstream point of view from getting proper representation, and exerted enough pressure to force a plebiscite. All this instead of our political institutions dealing with this through the standard channels of representation and accountability.

Thirdly and most toxically, Brexit has been heavily influenced post-referendum by our political culture. We are used to seeing the party that “wins” – that is, gets the most seats – implement their entire programme without any serious opposition. We do not often have coalitions, and we are not used to their attendant negotiations and compromises. So in the case of Brexit a narrow 52/48 win is interpreted by most Leavers and even a fair few Remainers as a mandate for the hardest possible Brexit. After all, Leave won.

From any neutral perspective this is crazy. A narrow win on such a major constitutional issue should be treated cautiously, and an attempt to find compromise solutions should have been pursued. The EU themselves are surprised at how partisan and polarised we are – but of course most European countries use proportional systems so they are used to compromise.

Viewed from this perspective, one of the sources of the toxic accusations of “treason” becomes easier to identify. The Leave side won, and in our system many people believe that means they get to do whatever they like. So of course anything that pushes back on this in any way can be painted as “treachery” – and that accusation will resonate with a lot of people.

The legacy of First Past the Post has toxified our political discourse so much that we are now risking an epochal split that will severely damage our country. Once the dust settles, we need a serious think about how we have got to this point – and our electoral system should be high on the list of culprits for reform.

Mark Thompson is a political writer and the co-host of the House of Comments podcast.