The Telegraph article Police checks for [EU] migrants (By Peter Dominiczak and Bruno Waterfield) suggests that unnamed British ministers are still woefully unaware of what they can do under EU law, or are possibly being misadvised by the Home Office:
Questions were immediately raised about how the Tories would be able to enforce deportations of out-of-work migrants, who are unlikely to appear on databases or official records.
However, a Cabinet minister familiar with the discussions said that migrants could be forced to register with police on arrival in the UK, allowing the authorities to check whether they had found work after six months.
“We are considering all options,” the Cabinet minister said. “And requiring migrants to sign in and register at police stations is one of the things we are looking at.”
Making new arrivals register at police stations is common practice in many foreign countries, and ministers believe it would be simple to impose here.
“Registering at police stations” or city hall is common practice in some European countries, e.g. Germany and the Netherlands. Where it applies to local citizens of the member state, it can also apply to EU citizens who are resident there.
But the Conservatives decided to scrap the requirement that British citizens have ID cards and continually register their current address with the government. British citizens are not required to register, and so EU citizens (and their non EU family) can not be required to register on this basis.
There can be no other requirement for EU citizens to register within 3 months of their arrival. The free movement Directive 2004/38/EC is very explicit:
Article 6 – Right of residence for up to three months
1. Union citizens shall have the right of residence on the territory of another Member State for a period of up to three months without any conditions or any formalities other than the requirement to hold a valid identity card or passport.
Member states presently have the option of requiring EU citizens to register, but the UK has never bothered to do so.
Article 8 – Administrative formalities for Union citizens
1. Without prejudice to Article 5(5), for periods of residence longer than three months, the host Member State may require Union citizens to register with the relevant authorities.
2. The deadline for registration may not be less than three months from the date of arrival. A registration certificate shall be issued immediately, stating the name and address of the person registering and the date of the registration. Failure to comply with the registration requirement may render the person concerned liable to proportionate and non-discriminatory sanctions
So a one-off registration requirement is allowed, but not earlier than three months after arrival. And failure to comply can be punished only with a “proportionate” sanction: Expulsion, for instance, would not be proportionate