Irish citizens, and British citizens too, don't have ID cards that can be used in lieu of passports. The previous British government brought in legislation to introduce ID cards, but I have to say that it proved to be desperately unpopular. One of the first things the present government did was to repeal the legislation, and this came into effect earlier this year. (Discontinuation of the identity card scheme was part of the election manifesto of both the parties in the current governing coalition.)