You don’t have to opt in to your right to free speech. So why do we have to opt in to our right to vote?

Voting is a basic right. While not enough on its own, the chance for ordinary citizens to have their say on their government is the core part of any democracy.

So we should all be worried by newly-released figures from the Electoral Commission which suggest that, as of last December, 17% of eligible voters in Great Britain might not be registered to vote. This means as many as 9.4 million people could be unable to cast their ballot if a snap election is called. And millions more entries are incorrect in some way.

Alarm bells should be ringing for those thinking of a snap general election.

Who’s missing?

Since registering to vote is something you have to do yourself in the UK, there are stark differences in registration levels – with younger people and renters missing from the register in greater proportions than older voters and owner-households. Understandably, if you’ve just moved flat and are juggling two or three jobs, registering to vote may not be number one on your priorities list.

Private renters are the least likely to have accurate and up to date entries on the register – with just 58 percent being correctly registered, compared with 91 percent of homeowners. Registration levels are also low amongst young people aged 18-34, with only 71 percent correctly registered, compared to 94 percent of people aged 65 and over. Make no mistake: this is a generation gap that threatens political equality in the UK.

It’s not a stretch to say that company accounts with this many errors – about one in six missing – would fail to pass audit. Our democracy is far more important than that.

Under-registration presents another hurdle for groups already underrepresented in politics. If people are not on the register by the time an election comes around, it can be the difference between being heard – and being totally ignored.

As talk of an election heats up, it means any snap election will almost certainly be based on a skewed franchise, with potential millions missing.

The problem

Unlike many European countries, in the UK people must opt in to their right to vote. However, there is no way for people to check online if they are already on the register, or to automatically enrol (the government scrapped the process whereby universities and colleges automatically signed up students a few years back).

That’s why the Electoral Reform Society and many more are calling for the urgent introduction of automatic registration or ‘motor voting’ opportunities – where people can opt in to the register whenever they engage with government bodies. DVLA, welfare and NHS records are often more accurate than local registration figures. So why not link them up? This is one easy first step towards fully automatic registration.

Other moves should include being able to check you are registered online. It’s bizarre that people often don’t know they are registered until they’re sent a letter from their council days after filling in the online form. This step would also prevent overstretched electoral registration officers dealing with unnecessary duplicate registrations.

We know tools like this work from other countries and following a detailed feasibility study by the Electoral Commission, we know it is possible here in the UK too. Rather than putting up more barriers through mandatory voter ID, we need to reduce the complexity of getting on the register in the first place. It’s a simple and clear way to reduce political inequality and ensure no citizen is left without a voice.

We desperately need a registration revolution that modernises the way we register to vote. This issue won’t dominate the headlines, but it’s absolutely fundamental.

It’s time to bring in the missing millions and ensure that at the next election – indeed in all future elections – the ‘missing millions’ can have their voices heard.