The AV referendum is probably going to be our last chance to express a view on how to choose our MPs for quite some time. I can’t see the issue coming back for about 20 years. So if you’re concerned about our democracy (or, indeed, if you’re delighted with it the way it is), the vote on 5 May is a crucial one.

Whichever side wins, one MP will still continue to represent each local area; whichever side wins, the voting system will be almost equally likely to deliver majority governments. We’re being asked, instead, which of two options is the fairer way of choosing our (single) local MP.

On that basis, in the full knowledge that the question here is AV versus FPTP and independently of the chances of any further reform, I’m hoping for a ‘Yes’ vote – and for what they’re worth, here are my main reasons:

1. With AV, a local MP will better reflect local people’s views

AV will make sure your MP’s views are nearer the real centre of gravity in your local area – and prevent a cohesive minority, who don’t really reflect most people’s views, from taking over instead.

For instance, imagine a seat where the Conservatives win 35% of the vote, Labour win 30%, the Greens win 25% and the Liberal Democrats and Socialists both win 5%. Leave aside the fact that the Tories only got 35% of the vote: as a matter of pure common sense, looking at the political consensus in this area, would a Tory victory really be a fair reflection of how most people voted?  It would be the same if Labour won 35%, the Tories won 30%, UKIP won 25% and the Lib Dems and English Democrats both won 5%. In both cases, FPTP delivers the seat to a party who is strongly opposed by most voters: AV would fix that.

2. With AV, no citizen will have to fear voting for their real first choice and getting their last instead

A general election should be your chance to weigh up what different parties offer, look at local candidates and make an honest statement of preference. It’s the only chance you get to express your opinion on what kind of Britain you want and who you want in charge and, hopefully, have some bearing on the outcome.

But for too many people, elections have stopped being an expression of belief and become a glorified game of chess. Keeping the enemy out becomes the only aim: voting ceases to function as an expressive act, a positive endorsement, and starts to be a defensive (often grudging) manoeuvre. And people who might have voted Green, Liberal Democrat or UKIP (or Labour or Conservative, for that matter) end up hiding their true colours and walking away from the polling booth feeling cheated. This is no way to run a democracy.

3. AV will make our political system a little more open

For better or worse, British voters have been gradually drifting away from the two largest parties. Labour and the Conservatives barely won 65% of the total vote in 2010; in 1951, they won nearly 97%. This has happened under a system which actively discourages voting for new parties. At the last European election, Tory and Labour support fell as low as 43.4%. Although I doubt we’d see figures quite that low in a general election, I do believe the current voting system is suppressing the real range of British public opinion.

There is an argument that the voting system should guard against a mass of tiny parties making the Commons unworkable: there’s not much of a democratic argument that it should try and stop any new political force from being given expression by the people. But FPTP preserves our party system in aspic: and if we ever saw a real surge in popular opinion, the voting system would crush it.

We’ve got the proof from the 1980s. The Liberal-SDP Alliance failed, but not because it couldn’t command mass support (25.4% of voters endorsed them even under FPTP) or because it had no credibility (the Gang of Four had all been Cabinet ministers). Ultimately, people didn’t believe they could win and didn’t take the risk. They might or might not have actually done so under AV: but if they had, an Alliance government’s economic policy would almost certainly have been a much better reflection of public opinion than Thatcher’s. It is very hard to believe that democracy was well served by the actual outcome, whatever your politics.

4. AV will produce governments with a stronger democratic mandate

Even if you want majority governments, their declining electoral mandate ought to worry you – and AV can help there. AV would, for instance, still have given Labour a majority in 2005. But Liberal Democrat voters were pretty repelled by Michael Howard’s campaign: most of them would have ranked Labour above the Conservatives. SNP and Plaid Cymru voters aren’t known for preferring Tory governments. 65% of people voted against Labour in 2005, but it’s almost certain that a majority of people preferred a Labour government to a Tory one: with AV, we’d have known that they did, and that broader (though, yes, less committed) support would have been expressed at the ballot box.

When we do get hung parliaments, we’ll also have a much better idea of what voters want their preferred party to do. If Liberal Democrat voters in 2010 preferred a Labour-Lib Dem deal, we’d have known about it from their second (third, etc.) preferences: equally, we’d have a better idea of whether the country preferred a Cameron-led government from preference data. With FPTP, we have no real way of knowing what voters want when no one wins outright: with AV, we do – and so politicians have fewer places to hide.

Finally …

Unless trends change radically, we can expect a number of things to happen under FPTP in the coming years. MPs will be elected with ever lower levels of public support. Governments will win majorities with smaller and smaller mandates from the voters – Labour’s 35.2% of the vote in 2005 could just be the start of things to come. Whether we get a government in line, even roughly, with the people’s wishes will become more and more a matter of luck, electoral geography and how many parties split the vote on which part of the political spectrum. And by the way, we’ll probably get a few more hung parliaments, whatever the voting system.

AV isn’t perfect and it won’t fix every problem. But it’s a better and a fairer way of choosing our representatives than the one we’ve got. MPs will have stronger mandates from their constituents – not a perfect mandate, not the whole-hearted support of everyone in their area, but a reasonably broad base of support in a multi-party system where voters can cast an honest preference. Governments will rely on broader support than they do now – and because they’ll need to maintain (qualified) support from other parties’ voters, they’ll be wise to govern in a way which reflects that broader support. And our political system will be better able to give big shifts in public opinion some form of expression, rather than just bottling them up.

If you want to be able to vote with your heart and your head at the same time; if you want governments to listen to a broad swathe of the people; if you want a politics which lets new people and new ideas into the debate: vote ‘Yes’ on Thursday.