If the National Identity card were just that i.e. a photo card confirmed with your identity then i doubt many would object but it is much more than that. All sorts of information is to be stored via it including your credit rating and goodness knows what else ( I wouldn't be at all surprised if DNA didn't enter into the fray at some point) .
This is introducing a national scheme by stealth a supposedly non compulsory scheme which will be compulsory or you lose your job. Every airport worker wears an ID badge already, if there are problems with that scheme then reinforce that rather than bring yet another security check. I doubt if the badge they give you from a national scheme will be compatible with airports security systems so either airports have to bring in a new one at great expense or people have to carry around 2 badges of ID.
National Identity cards do not improve national security, and when the terrorist crimes committed in the UK over the last 3 decades were in the main perpetrated by British Citizens anyway who are they trying to kid. It's just another way of reinforcing Big brother Britain