Italys' current Id card is not biometric or compulsary at the moment, AFAIK it's basically a photo and DOB (which isn't all that different from a passport). One of the major concerns of the UK ID card scheme is the volume of personal information upon it, the issue of being forced to have to prove your identity, and crucially the technology issues; specifically, it'll provide a method of tracking movements via tracking card-check accesses (plus it has RFID for remote reading), and a system where it's easy to 'snoop' on peoples records (owing to a central database designed to facilitate this purpose; this is different from the likes of seperate passport and driving license registries, which have current legal and technical barriers to muck-raking). There's also the issue that the legislation IIRC allows extensive and effectively arbitrary powers to alter the data required upon the card, etc, once passed. And that the government wants to use the card to allow or deny services, such as NHS treatment, which has a massive impetus for discrimination.
Not to mention the financial aspects, which the government has refused to reveal (we're looking at billions of pounds in startup costs, at least £500m per year for the Home Office alone - the only figure the government has revealed - and god knows how much for other affected departments).