All those that work at airports already have data given to a private company. That company then issue an ID card after checks have been done.
Yet, so far as I am aware no one has worried about that company holding the information they do, nor what use they put it too.
All staff at airports are now CTC vetted. Ok, that vetting is a low level one, consisting of a PNC check, and a check with Special Branch and with a group who have a PO Box number as thier address.
Have those records been comprimised? Erm, not that I can recall, with the exception of the odd bent copper in the past. Now, it's far harder to do a false PNC check, and the penelty, ie a stay in one of HM Guest Houses, makes it not worth doing.
On the surface, the scare senarios of what if my DNA is found somewhere there has been an offence may make sense to those who have written them. From the other side of the coin, those scare senarios don't hold very much water. It's easy to assume the events discribed, in reality all DNA does is indicate someone may have been there. It does not alone prove guilt.
Yes, you may get arrested because of it, although, it's not a definate. My DNA, and fingerprints are still on the Police system (because I was a Police Officer, not because I've been nicked!). I have no fears about them being there. Again, so far as I am aware, neither the National Fingerprint Collection, nor the DNA database have been comprimised.
Some people will talk (or not talk) themselves into being charged with things they haven't done, that isn't going to change because of ID cards or a national ID card system.
I've sat the other side of an interview room table, desperatly trying to get an explanation from a suspect, because although the evidence is strong enough to charge him, I don't believe he did it, and been thrawted in that either by solicitors telling thier client to say nothing, or through the suspect lying because he thinks that will get him out of it. Like 99.9% of police, I had no interest in convicting someone who wasn't guilty.
As for ID cards themselves. The assumption is that any organisation can get access to everything on it. They wont. DVLA will not be able to see your National Insurance details, because they don't need it. Nor will your Town Hall be able to look at your medical records. There is already legislation that prevents access to information that there is no need to have.
As someone has already said, with a few details you'd be suprised how much data there is about you already available, and fairly unrestricted. Yes, The NIR will have more, but all that 'more' will be is a central database which holds the information currently available as the result of 8 or 9 checks.
On the subject of 'discrimination' against those that work on airports. Yes, I agree. It's either ID cards for all, or no one.