Now I may be totally wrong here, but I think I read somewhere that passports are not legally required at all, it's just that it has become a very uiseful form of ID that airlines etc demand as part of their process and that's the same for entry etc all over the world. For example I once read Boy George's column in a Sunday paper and he explained how he lost his passport the day before flying to somewhere or other and by contacting the embassy was able to get an invitation to vist that country and hence was able to travel without a passport. I'm pretty sure I didn't dream this! No doubt someone will let me know if it's total B0ll0cks!