The idea that our first-past-the-post (FPTP) voting system is a good way to bring about socialism is totally unique to sections of the UK Labour Party. For example, the left-wing Campaign for Labour Party Democracy not only say they support FPTP on the basis that “PR would mean no majority Labour governments”, but that this support “derives from our commitment to socialist values and socialist advance”.

If true, that would mean British socialists are the only real socialists, because there are no other socialist parties in the developed world that support FPTP. Stranger still, it would mean there are no successful socialists at all, because all the countries that have these socialist-friendly elections have failed so badly to deliver socialist outcomes.

When you talk about proportional representation (PR) in the Labour Party, as Make Votes Matter and the Labour Campaign for Electoral Reform are doing, you are mainly met with resounding support. In fact, 54 CLPs have now passed resolutions in favour of PR. But even among supporters of PR, there’s a feeling that by making all votes count equally we’d be giving something up: a tantalising shortcut to socialism that only FPTP offers. But there is zero evidence that FPTP is the best way to create a society “for the many”.

The abysmal record of FPTP

Most major developed countries use some form of PR for general elections. FPTP is used by just three: Canada, the UK and the US. If FPTP is as beneficial to socialist advance as CLPD claim, then these countries should be head and shoulders above the rest in terms of socialist outcomes.

But they’re not. Take income equality. Of 35 OECD countries, the UK comes 31st. The US is 33rd. Canada performs a little better, though still below average, coming 20th. In terms of the poverty gap, Canada is 19th out of 35, the UK is 31st, the US is 34th.

Here’s the kicker: while the UK has had Labour governments for 41% of the time since 1955, Canada – by far the most egalitarian of FPTP countries – has never had a socialist majority government. Not only that, but Canada has had hung parliaments much more often: 35% of the time since 1900, compared to the UK’s 23%.

So the idea that FPTP allows us to build a better society by enabling socialist majority government is baseless. By far the most equal country with FPTP has never had a socialist majority government – and much less majority government in general.

Hung parliaments are something shared by the world’s most equal societies, which all use PR. Neither Denmark, Norway, Belgium, Iceland, Finland, Sweden or even Germany or the Netherlands has ever had a socialist majority government – and they all wipe the floor with Canada, the UK and the US in terms of economic equality. Indeed, the relationship is so strong that political scientists suggest a causal relationship between PR and reduced inequality and poverty.

What’s going on?

Why are countries that have never had a socialist majority government so much better at delivering socialist outcomes? Part of the answer is that a system that produces socialist majority government also produces right-wing majority government. The left makes progress when in power, but it’s easily undone when the pendulum swings back.

But in reality, countries with FPTP have right-wing governments more than half the time. A study by Harvard and LSE professors Iversen and Soskice cited proportional democracies as tending to have left-wing governments three quarters of the time, while in majoritarian systems it’s the other way round.

This fits with the UK’s experience. Most people have voted for parties to the left of the Conservatives in 14 of the last 17 general elections, yet the Tories have been in power for 62.5% of this period, rising to almost 65% if May’s government lasts its term. So the left is always playing catch-up when it gets in. Even our 2017 manifesto – undoubtedly radical compared to past UK policy – contains little that a centrist in Denmark would raise an eyebrow at.

According to Iversen and Soskice, this conservative bias arises because progressive parties can only succeed in FPTP when they unite vast sections of the electorate under a single banner. Doing so is tricky. The most reliable method has been to water down your socialism and pitch towards centrist voters, knowing that left-wing voters’ only real choice is between you and the right.

This explains the electoral success of Tony Blair, and why Canada’s “left-wing” party, the really quite right-wing Liberals, have been in government far more often than the UK Labour Party. It also explains why no developed country with FPTP has had a government that left-wing groups like CLPD would call genuinely socialist for 67 years.

The solution is not for Labour to pander to centrism under FPTP. On the contrary, the evidence is that campaigning unashamedly for socialism under a proportional system is far more likely to create the society we want.

And none of this is to say that Labour won’t win a majority on a socialist platform again. I think we’re as close as we’ve ever been to that once-in-a-century event: a Labour majority swept to power on (what is by British standards) a radical manifesto.

But if that does happen we must bring in PR, because nowhere has the long-term effect of FPTP been the advance of socialism; instead it has meant decades of falling behind. And there’s simply no reason to believe the long-term trend will be different in the future.

If you want to learn more about why Labour should back PR, invite a speaker to your CLP or trade union branch.