Another cast iron pledge from cameron?
He has broken so many of his promises now, I doubt he'll keep this one either. Chances are the incoming tory government will like the idea of ID cards and will press ahead with the scheme anyway. Of course there's also the EU to consider. They like ID cards as well. There is no EU "id card directive", but they want EU member states to implement biometric identification documents in the form of passports. Now that Lisbon is coming in to force, making the EU our de jure government, it may well be that a future Cameron government will be told to implement an ID card scheme regardless of whether or not he wants to keep his promise. In that instance what can he do? Nothing.
Whatever the case, don't rely on the promises made by the tories. They can't or won't keep them.