Iona that's unfair. Passports are expensive and a right faff to get hold of. Filling out the form and getting it witnessed is a huge challenge for many poor or vulnerable people. If they don't expect to be going on holiday in a hurry it's easy to see why it's not a priority for them.
If a passport costs £60 or whatever it is now. plus photos, the travel involved in sorting it all out, the stress of finding someone who knows you well enough to witness it (not easy for people who don't count bank managers and head teachers and doctors among their mates) and that's the only way you can vote, I can well see why plenty wouldn't bother.
You are absolutely right that a good proportion of them are completely disengaged and still wouldn't bother even if you paid for the passport and put it right in their hands for them, but to claim that all poor people are just too lazy and feckless to make it a priority is grossly unfair.
I reiterate what I said earlier, I think it's high time we had better systems in place for IDing people and preventing electoral fraud and I'd support an ID card for all. But if that isn't to be rolled out then the governemnt should come up with a voluntary scheme that is free for people who lack the usual forms of ID but would like to have something that entitles them to vote or just prove who they are. It could be done (photos etc) at libraries, job Centre's, GP surgeries etc as a sort of mobile service.
Quite honestly,, I think the uptake would be pretty poor in certain sections of the community as many people would distrust the system and see it as being snooped on or singled out, but that's up to them. The option would be there, if they wanted to vote they'd know what they needed to do.