WHITHER the "missing million"?

Figures uncovered by The Herald appear to contradict suggestions that a surge of new voters, previously eligible to vote but unregistered, could have a decisive impact on the outcome of the independence referendum.

There is little evidence this is happening.

In some of Scotland's most deprived wards the numbers registered to vote are little changed now from the figures in 2012. In some cases, the numbers listed appear to have fallen, rather than risen.

It is pretty clear there has been no significant surge to join the roll from voters energised by the Yes or No campaigns, or signed up by canvassers ahead of this month's poll.

Overt calls for supporters of independence to engage with and register polling station refuseniks mean this may be a particular disappointment for the Yes campaign.

However, the numbers of eligible voters who are not on the electoral roll is actually relatively small. Around nine in ten of those eligible to vote are already on the roll, meaning many fewer than a million are wholly outside the system. In fact, that figure is little more than a soundbite. Many fewer than a million are unregistered, while many more than a million Scots failed to use their vote in the last election.

The best way of understanding the reference to a "missing million" is as a handy shorthand for those eligible to vote who never normally do. This is the group highlighted by Alex Salmond and other Yes campaigners as potentially key to the outcome.

But are they such fertile territory for Yes canvassers? As we report today, psephologist John Curtice has analysed findings from polls of people who did not vote in previous elections.

Quite contrary to many people's expectations, non-voters are, by his account, less likely to vote Yes than the population in general.

That is likely to give succour to the Better Together campaign and assuage worries that a high turnout from disengaged people who don't normally vote could help overturn the lead for No in the polls.

It also suggests that many on both sides of the argument live in a relative bubble, interacting largely with each other though traditional and social media. There is a sizeable section of the voting age population who remain completely disengaged. In other polls this might have been attributed to dissatisfaction with the range of candidates on offer, or knowing their votes would not affect the outcome.

Yet, even during this enthralling and critical debate, with the result potentially so close enough that every vote matters, and on the very day of the voter registration deadline, some people remain reluctant to engage.

It is worrying for the politicial process that significant numbers are so democratically excluded.

Whatever the referendum's outcome, addressing this should be a priority for politicians of all stripes.

Solutions might include more proportional representation, same day voter registgration as happens in some US states, or even compulsory voting. But this is a problem which will remain after the dust of the current battle settles.