A senior political figure who shall remain nameless, but is currently mayor of London, once told me that on the final day of general election campaigning he had just enough time left to visit one of two places: a students’ hall of residence or an old people’s home. He chose the old people’s home.

The calculation was clear: it was in the old people’s home that he stood the better chance of meeting actual voters. To his credit, he knew something drastic needed to be done about this, but it was a sad acknowledgement that in politics the young are nowhere near the front of the queue.

Around 75% of people aged 65 and over will vote in this election; unless something thunderously radical happens in the next six weeks, only around 42% of 18- to 24-year-olds will do the same. The over-65s coming out to vote and the under-24s staying in has been the norm for the past few decades. This is why we’re now all hearing so much about the pros and cons of the triple lock on pensions, but absolutely nothing about student fees and housing benefit.

The older electorate has become an effective voting lobby, more powerful than the gas industry. Because the over-65s turn out in such large numbers, every politician needs to court them and doesn’t want to utter a single word that will alienate them or drive any of them to political opponents.

Why can’t it be like this for 18- to 24-year-olds? If they registered and voted in force, they would become powerfully unignorable. I admit that “Powerfully Unignorable” is not a great campaign slogan, but it’s much better than “Mostly Forgotten”.

Of course, a lot of young voters choose not to vote because they’ve been put off by what’s on offer. When the prime minister asks to consult the electorate but refuses to be consulted by it in televised debates, what’s the point of joining the discussion? When parties steal each other’s tactics and policies – Labour going all out for Brexit, the Tories pinching old Ed Miliband policies such as caps on energy bills, and the Lib Dems, the party of coalition, declare they will not do coalitions, then it’s easy to wail, “they’re all as bad as each other” and stay indoors.

But the reality is this is an act of protest that immediately becomes a self-fulfilling prophecy. It’s no coincidence that the collapse in the 18- to 24-year-old vote has seen the advent of tuition fees, reductions in housing benefit for 18- to 21-year-olds, the scrapping of the education maintenance allowance, no entry to the “national living wage” until the age of 25, and cuts to student disability allowances.

These are measures taken in recent years by Labour, Conservative and Lib Dem ministers alike because, in the end, the youth vote was never going to trouble them. So, if financial savings were going to have to be made somewhere, they were going to be made from young people. This in turn has produced disenchantment: if the young are going to be so neglected, why should they bother voting? And so it spirals on: each reduction in registration and turnout met with a further opportunity for ministers to raid young people’s resources. While older voters are invited to the top table, the young are dumped around the back by the bins.

That’s why, for this election, I’ve been joining others and urging 18- to 24-year-olds to reverse this cycle by registering to vote and then getting out and using that vote. My advice doesn’t get any less basic than this: just vote. Yes, I assume a large percentage of young voters are likely to vote for progressive parties. That’s great. I’m all for it.

But really, each vote is each voter’s privilege, to do with what they like. So, go out and vote any which way you think is best. Vote for who you really believe in. If you don’t believe in anyone, vote for who you think might make any kind of difference, whether it’s to your constituency or to the makeup of the next parliament. Vote with your heart or your head, I don’t mind; that’s your quiet moment. Spoil your vote if you want to. Just get out and vote.

The material benefits are clear. If young voters turn out in large numbers, then they become a powerful bloc that needs to be heeded and addressed. It’s the basic politics of self-interest: the more 18- to 24-year-olds vote, the more their concerns will be taken seriously.

But there’s idealism in this too. It’s about keeping democracy healthy. If we don’t participate in democracy, we won’t have much of a democracy left in which to participate. The truly wasted vote is the one that isn’t cast.

Don’t get me wrong. I’m not ignoring the fat sheaf of opinion polls predicting a huge Conservative majority. But it makes me all the more determined to point out to voters the many ways a vote can still be used effectively.

Although we were all mostly appalled by Donald Trump’s victory, there is some consolation that he has the courts and Congress placing checks and balances on him. In Britain, we don’t have these restraints. Total power resides with the prime minister. The bigger the majority, the more unchecked her (or his) sway across health, education, taxation, benefits, and indeed all legislation, not just Brexit negotiations.

And it is possible to act to stop that majority from growing, if that’s what most concerns you. It’s now possible to find out via websites such as Votingcounts.org.uk, Tactical2017.com and Compassonline.org.uk what the best option is in your constituency.

For too long, politicians have played a cynical game in which they target the slim minority of the electorate who hold the balance of power – the target seats with slender majorities, the swing states, the key regions. It’s a system that took an awful lot of the electorate for granted. That system ran aground last year. Populist explosions not just for Marine Le Pen and Trump but for the likes of Nigel Farage, Bernie Sanders and Emmanuel Macron in France are the extremely loud shouts of frustration from whole sections of the electorate who have been feeling more ignored or taken for granted. It has made the electorate more unpredictable, more loudly disloyal, which in turn has stirred fear in established political parties. In short, the parties don’t know what we’re up to, and they really don’t like it.

That’s good, because it puts power back where it belongs, with the voter. The downside, though, is that votes can go in either direction. Brexit, the election of Trump, the rise of Le Pen, Recep Tayyip Erdoğan’s increasing autocracy in Turkey; these are the will of democratic electorates. Unpredictability is extremely unpredictable. Votes matter and those who don’t vote risk getting not more of the same but the opposite of all they believe in.

HOW THEY VOTED

Facebook Twitter Pinterest Ipsos Mori analysis suggested that 43% of young people supported Labour in the 2015 general election, while 27% supported the Conservatives. Photograph: Alamy Stock Photo

■ Since 1992, voter turnout has fallen – with the sharpest declines among voters aged 18-24 and 25-34.

■ In 1992, 75.4% of 18-24s voted, but this dropped to 44.3% by 2005. Among 25-34 year olds, the number of people voting fell from 86.6% to 55.2%, according to British Election Survey data. In 2015, it is thought the turnout among those aged 18-24 rose to 58%.

■ The turnout among 18-24s in the EU referendum is thought to have been higher than anticipated at 64%, the London School of Economics says.

■ Ipsos Mori analysis suggested that 43% of young people supported Labour in the 2015 general election, while 27% supported the Conservatives.