“It will be they who will live with the consequences of the vote longer than any of us.” The Labour peer Sally Morgan was talking about the referendum on EU membership. “They” are 16- to 18-year-olds, 2 million Britons who will probably now have a say in the matter as the result of a House of Lords amendment. But her comments remind us of a deeper political truth: decisions taken now affect the courses of young lives to a greater extent than our own.

The difficulty is that many of those born since 1990 have decided simply not to bother with the conventional political process. The statistics are shocking: only 43% of 18- to 24-year-olds voted at the 2015 general election (down from 44% in 2010), compared with 78% of those aged 65 and older. This is a crisis of non-participation. Some will grow into politics, of course. But current levels of disengagement are more or less unheard of – and threaten the future legitimacy of our system of government.

There are occasional exceptions to the pattern: turnout was vastly higher in the Scottish referendum, for example, although the age imbalance was still in evidence. And though the detailed demographic work has not been done, Labour officials believe Jeremy Corbyn was particularly popular with young people in the party’s leadership election. Broadly speaking, however, this problem isn’t going anywhere.

How did the habit of not voting become so ingrained? Some see it as a consequence of fundamental shifts: the breakdown of class loyalty, of party politics; the inability of a cadre of nerds and aristos to compete with celebrities and internet memes. Those things seem hard to do anything about. What if there were a much simpler solution?

No one could be expected to understand the relationship between the House of Commons and House of Lords – the Salisbury convention, the parliament acts – without having been told about it. Local government, Whitehall, the European commission: these are not straightforward relationships. It’s difficult to read the British system, and political illiteracy is rife.

I was lucky enough to get a good training in the mechanics of power from Ms Puttock, Ms Hancock and Mr Blunt. The comprehensive I went to offered an A-level in government and politics: there were six of us in the class. Up to that point, my formal political education had been non-existent. After a couple of years I felt I knew something about the forces that shape our economy and society. And that meant I was interested in influencing them. There is no election, local or national, that I haven’t voted in since.

That knowledge boosts engagement isn’t just a hunch. A large Harvard analysis found that students who completed a year of coursework in American government or civics were three to six percentage points more likely to vote after high school. The effect was even more pronounced among students from families where politics was rarely discussed – where the difference was seven to 11 percentage points. For those young people in particular, teaching helped fill gaps in their understanding unlikely to be plugged by any other means. This is a clear democratic dividend. If politicians want to boost turnout, they should worry less about what music to pretend to listen to, and focus on making sure that everyone gets a decent political education.

Isn’t that happening already? Not really. One of the first things David Blunkett did when he became education secretary in 1997 was to ask his old politics lecturer, Bernard Crick, to look at the state of play in England and Wales. The result was a move to make “citizenship”, a subject that encompassed democracy, conflict resolution and ethics, part of the national curriculum. Despite this, it never properly took root.

Alan Johnson, in charge of education from 2006 to 2007, admits citizenship education “has been patchy”. “When I was secretary of state,” he tells me, “it was very new and there was perhaps a bit of an excuse for it taking time to settle down. But nothing much seems to have changed.

“We’ve got a problem in this country in that people stumble into adulthood without any idea of the kind of responsibilities placed upon them as citizens. I’m depressed that it’s not improved over those years.”

Jeremy Hayward, at London’s Institute of Education, paints a similar picture. He explains that citizenship used to be popular as a half-GCSE. Less than a decade ago nearly 100,000 pupils took it each year along with another subject, often religious studies, to make up a whole qualification. That was until new rules made combining courses in this way impossible. Numbers dropped precipitously, with many opting for a full GCSE in religion instead. However, as Hayward points out, there’s now a requirement to teach “fundamental British values” (FBV) that extends to all schools. Among many other things, the aim is to increase “support for participation in the democratic processes” and familiarity with public institutions.

But FBV falls within a broader strand known as spiritual, moral, social and cultural development (SMSC). The basic political toolkit – knowledge of voting systems, legislation, parliament and cabinet – is likely to get lost in this alphabet soup. And are students really best served by an ideological programme designed to inculcate specific beliefs, rather than one that explains the nuts and bolts of the constitution? I don’t think so, and Johnson agrees: “Values – honesty and obeying the law and compassion and concern for others – that should be part of every child’s experience of going through the school system. But what you’re really trying to teach is the prose, rather than the poetry – this is how the system works, this is how you engage with it.”

I track down Ms Puttock, now Mrs Outhwaite and an academic at Warwick University. Back in 1996 she was fresh out of university, a specialist government and politics teacher. “I loved teaching politics,” she says. “Students would say, ‘I now understand what’s going on when I watch the news, I now understand what it means when I read a manifesto, I can see how this has moved me on in my thinking’.”

But when I suggest compulsory political education for under-16s, she’s hesitant. With citizenship, she explains, “what happens is that instead of it being taught really well by people who are qualified to teach government and politics, it’s taught badly by physics teachers. So in an ideal world, yes, you’d have a body of committed social science teachers who are trained and would be able to deliver it.”

But that’s not where we are. So much so that when politics teachers gave evidence to the Power inquiry, chaired by Helena Kennedy, they said it was too soon to extend the franchise. “We didn’t have political literacy at the level I thought we needed if we were going to allow 16-year-olds a vote,” says Outhwaite, who was part of the delegation.

This is a serious indictment of the state of our democracy, one that will become more embarrassing as we give young people new opportunities to participate. That is the right course to go down. But the prerequisite must be outstanding political education, with testing, for all.