Prospect will campaign against the introduction of ID cards, and are doing so at the moment. Your question to a rep that if you are required by law to have an ID card, as it will come into force through a bill in parliament, would prospect defend me if I say no to having one is somewhat strange. Whilst Prospect, and I refer to the ATCO Branch, continue to campaign against the cards, it is difficult to defend somone for breaking the law if they are introduced. I would suggest you join the campaign against them by writing to your MP, MEP and supporting groups that are openly campaigning against them such as liberty etc. Like you, I am 100% against them, and see airports as another means to make something we are continuosly told is not compulsory suddenly compulsory to vast swathes of the workforce.
Good luck in the fight against ID cards