Media playback is unsupported on your device Media caption Nick Robinson gauges apprentices' opinions on voting

"Can I get you to vote?"

That's what I asked when I took my ballot box to the hair salon to ask a group of apprentices whether they're going to bother.

Their answers - which you can see in my TV report - were revealing. Some argued there was no point because the system was rigged against them and nothing changed. Others insisted that if you didn't vote you couldn't change things.

Today is National Voter Registration Day and a new opinion poll has shown that as many as 800,000 young people aged 18 to 21 will not be able to vote in the general election because they're not on the electoral roll. That poll for the Electoral Reform Society also showed that 24% of 18-to-21 year olds haven't registered to vote. Another 9% had no idea whether they were on the register at all.

Call it apathy, call it disaffection, call it what you like, it's a problem. Politicians will always focus on those who might vote for them and increasingly that means older people.

The new system of individual registration is making that problem worse. You used to be able to rely on your college or student union - or Mum or Dad - to do it but now you have to register yourself. Having said that it's easy to do - taking around three minutes online.

It is, of course, your choice whether to vote and who to vote for but if you don't register that choice has gone.