It is possible to achieve great change in Britain without your campaign requiring million-pound donors or years of carefully cultivating media proprietors and their editors. Established and seemingly settled laws can be overturned without securing television and radio airtime, or by setting-up campaign call centres, local and national managers, exceptional public relations advice and expensive lobbyists.

Take the case of lowering the voting age to sixteen, an issue so low on voter priorities that it has never even generated its own Twitter storm. It first made the parliamentary agenda in 1999 when the Lib Dem MP, Simon Hughes, proposed and lost (by 434 votes to 36) a Commons amendment to introduce it.

It duly became his party’s policy in 2001 and two years’ later a ‘Votes for 16’ coalition of supportive youth groups was formed. Its website, set-up by the British Youth Council with support from the National Union of Students and the Electoral Reform Society, currently boasts that 4,290 have signed up to the cause. This is hardly a mass movement. It was the attendance when Dunfermline Athletic played Alloa Athletic last month.

Yet, look at the success it has achieved. It is now the policy of the Labour Party, the Liberal Democrats, the SNP, Plaid Cymru and the Greens.

Labour’s 2019 manifesto pledge to give the vote to sixteen year olds was not just for Westminster. Had Labour won that election, John McDonnell confirmed that it would give sixteen year olds the vote in the second referendum the party planned on Brexit.

Scottish sixteen year olds got the vote in the 2014 independence referendum. Why? Because the SNP’s research suggested that the 124,000 duly enfranchised were more likely to vote ‘yes.’ The following year, Holyrood passed a bill that also gave them the vote in local and Scottish parliament elections. The vote to do so was unanimous – David Cameron having waved through granting Holyrood the authority to change the voting age (as part of his ‘vow’ on the eve of the IndyRef, Cameron had supported the establishment of the Smith Commission to propose devolving further power – of which this proposal turned out to be one).

Where Scotland led, Wales has followed. Last November, the Welsh Assembly voted to enact legislation that will ensure sixteen and seventeen year olds will be able to vote in local and Assembly elections in time for the election for the 2021 Assembly (or Senedd as it will by then be called).

The case for withholding the vote from an age group who are deemed not old enough to smoke, marry or use a tanning salon, ought to be obvious. 90 percent of sixteen year olds are still classified as schoolchildren. Last year, 1,820 of sixteen and seventeen year olds signed-up to join the army but because of their youth are prevented by law from serving on the front-line. Even with this protection, their recruitment is widely condemned as the British Army’s reliance on “child soldiers” – although rarely by the sort of social campaigners who would brand their enfranchisement as that of “child voters”

In response, it is certainly an argument that sixteen year olds should elect a government whose policies have consequences from them. Then again, legislation also concerns all ages of juvenile, without “effect” and possible enhancement of their “engagement” being deemed the yardstick for their enfranchisement.

Outside Latin America, almost every country in the world retains eighteen as the voting age in national elections (Austria and Malta are the main exceptions). That Cardiff and Holyrood now have different voting ages to Westminster does not, of itself, mean that the latter will tire of being the anomaly on the mainland. After all, Westminster has not followed the versions of proportional representation used by the devolved powers. But the reasons that all the main parties at Westminster apart from the Tories now want to lower the voting age is why this measure has a good chance of being eventually adopted, even although it generates so little public interest.

The reason that the ‘votes at 16’ campaign has persuaded the opposition parties is not one of principle but of politics. They all calculate that lowering the voting age adds almost 1.5 million voters who are overwhelmingly anti-Conservative (and, for what it still matters, anti-Brexit). Party and ideology advantage is the calculation, the only meaningful calculation.

It is for the same partisan arithmetic that the measure will not be introduced wherever the Conservative Party holds power. Before December’s general election, the cause was openly endorsed by only 7 Tory MPs. With the subsequent departure from the Commons of Glyn Davies, Luke Graham, Justine Greening, Nicky Morgan, and Sarah Wollaston that leaves just Peter Bottomley and John Lamont as returned Tory MPs waving the flag for school-age voting.

There is, then, no appetite in the party of power to change the Westminster voting age. But the Conservatives will not win every Westminster general election forever. Is votes for sixteen year olds therefore inevitable?

That depends on whether pollsters find signs of a revival of Tory sentiment among young people. If so, it might magically cease to be a priority for the other parties. Otherwise, sooner or later, playground politics is on its way.