Yesterday the Scottish parliament made history by passing legislation allowing 16- and 17-year-olds to vote in next year's independence referendum. Holyrood should be proud of its role in extending the franchise: young people desperately need to be brought into our democratic structures as early as possible. But the move also exposes the absurdity of granting people a vote in such an important referendum, but denying them the right to elect their own representatives. It is time for all the political parties – in Westminster as well as the devolved governments – to get behind votes at 16.

Political disengagement is an ever-intensifying problem and especially so for young people. Only 12% of those aged 18 to 24 now say they are likely to vote, down from an already depressing 30% just two years ago. This early disaffection directly affects the likelihood of people to vote later in life. The American researcher Eric Plutzer describes voting as a "gradually acquired habit". If you do it early, you will do it often.

But if you start off on the wrong foot you are more likely to fall into the habit of non-voting. The 16- and 17-year-olds voting in next year's Scottish referendum are being given a helping hand on the road to a lifetime of good citizenship. It is crazy to deny this help to other young people around the UK.

Voting ought to form a crucial part of a young person's education. By the age of 16, thanks to citizenship education, young people have learnt about how our democracy works and why it is so important to vote. Yet they are not allowed to exercise their most basic civic right for another two years, creating a dangerous gap between education and practice. Next year's referendum will be the first test of what happens when young people are given the opportunity to put citizenship education into practice while it is still fresh in their memory. We should not be surprised if this cohort goes on to show higher levels of civic engagement in the future. The danger is that their contemporaries around Britain, and indeed subsequent generations of Scottish young people, fail to match them.

This is not about giving young people what they want. Among 15- to 19-year-olds, more than half prefer to maintain the status quo, with the most popular reason being that those under 18 lack life experience. Nor is it just about giving young people the rights that their responsibilities as taxpayers, soldiers and contributors to society warrant.

It is about seeding a respect for democracy at an early age, and encouraging people to get into the habit of voting. We should challenge the commonplace assumption that politics is an activity reserved for a narrow band of elites, and that voting is pointless. By enhancing civic education with the right for 16- and 17-year-olds to vote, we could do just that.

Yesterday's legislation in Holyrood is a landmark moment, but it is a one-off. Politicians around Britain should take this opportunity to build a lasting legacy by lowering the voting age for all elections.