In 1986, the French president, Francois Mitterand, had a ruse to protect his Socialist Party from being thrashed in the majoritarian system used to elect deputies to the National Assembly: introduce proportional representation. The ploy was far from successful, since the Socialists lost a quarter of their seats. Mr Mitterrand’s aim of weakening the mainstream right, however, did rather better, as the RPR-UDF coalition that formed the next government had a razor-thin majority of only two seats.

But there was another byproduct: for the first time the National Front entered the assembly in strength, going from zero to 35 deputies. Many attribute the party’s rise from the fringes to Mr Mitterrand’s cynical decision of over 30 years ago, setting in motion a process that culminated last Sunday in Marine Le Pen winning a place in the second round of the French presidential election. Many analysts warn that a Le Pen victory cannot safely be ruled out.

If that is an instance of a decision having long-term unintended consequences it is also something else: an example of how an electoral system – a means to express the will of the people – can end up shaping the statement of that will in ways that may not appear to be particularly democratic, or not reflective of what most people actually want.

For instance, the conversation about the forthcoming United Kingdom general election, it is widely agreed, will be all about Brexit. But it ought to be about something else entirely as well. And that is that the electoral system in the UK is now totally unfit for purpose and needs reform for any government to have serious legitimacy.

Britain would have had this discussion after the last election if it had produced another hung parliament. The surprise majority won by David Cameron and the Conservatives meant, however, that anomalies such as the United Kingdom Independence Party (UKIP) winning four million votes but only one seat, while the Scottish National Party won 56 seats out of 59 in Scotland with only one and half million votes, were briefly noted and then ignored. Parliamentary life went on as normal.

That “normal”, however, no longer works. For the first-past-the-post voting system that the UK uses, which gives “winner takes all” results in each constituency, works well enough in a two, or two and a half, party system. And its strongest justification – that under first-past-the-post electors can vote for a strong government, and equally clearly vote to kick them out – was persuasive for the near century in which the choice was mainly binary. Governments were going to be either Conservative or Labour. (And bad luck to the Liberals who got squeezed out almost as badly as UKIP did in 2015.)

But Britain now has a multiparty system, with the Conservatives, Labour, the Liberal Democrats and the SNP all winning substantial sections of the electorate. With none of the last three in any danger of winning the around 40 per cent of the vote required to win a parliamentary majority in the foreseeable future, however, that guarantees a Tory government in virtual near perpetuity.

This is not to make an anti-Conservative point. It is to ask how it can be democratic for the roughly 60 per cent who habitually do not vote for the Conservative Party to have no chance of their voices being represented in government for years, maybe decades?

Some form of proportional representation is the answer, such as is used in countries around the world from Germany and Ireland to Indonesia and Turkey. The objection to proportional representation is that voters don’t know which parties will end up partnering with which after the election, and hence they cannot vote for a particular government.

It could be argued, however, that under first-past-the-post, the last time electors in Britain got the government they voted for was in 1931 – since that was the last occasion any party secured over 50 per cent of the vote. Every poll since has been won on a minority, with that supposed election-winning genius Tony Blair scraping out his last victory on only 35 per cent. Did that really represent the will of the people?

Because of the way it skews results, first-past-the-post also occasionally throws up quite shocking results. In 1993, for instance, prime minister Kim Campbell of Canada called a general election – after which her Progressive Conservative Party, which had been a majority in the country’s House of Commons, was reduced to only two MPs. In any state with proportional representation, the 16 per cent of the vote the Conservatives secured would have meant that duo would have been joined by others, and they would have been a force to be reckoned with. Instead, it was the end of the party.

The lesson to be drawn from these examples is that different electoral systems may be right for different countries, and also at different times. Making a fetish out of one particular system is foolish, since it is the expression of the people’s will that matters, not the process by which it is articulated. But it is also that tinkering with a system – as in Mr Mitterrand’s case – or insisting on retaining it when it no longer performs its purpose adequately (as the Conservatives do in the UK) for selfish political ends, has a habit of coming back to haunt you.

If Britain had an electoral system that allowed people’s voices to be properly heard, there may have been no Brexit; for that was at least partly a protest vote. And if Mr Mitterrand hadn’t been too clever by half back in the mid-80s, the spectre of the far-right claiming the presidency of France might not be before us today.

Short-term tactical advantage is always tempting. History shows, however, what damage it can do. Electoral systems must serve the people, not the politicians; otherwise both may suffer in the long run.

Sholto Byrnes is a senior fellow at the Institute of Strategic and International Studies, Malaysia