Nationals of the member States of the European Union benefit from more favourable provisions of immigration law than nationals of other countries. If you are a national of a European member State, do not assume that the general law applies to you; check for special provisions. Four groups must be distinguished:
Nationals of European Union countries in general. You are free to come to the UK. You can visit, work, whether for an employer or for yourself, and study. Workers can bring a wide range of family members with them, whether or not these family members are European Union nationals themselves. Students can bring immediate family members.
Nationals of Romania and Bulgaria, the most recent members of the European Union. Nationals of these countries are, since 1 January 2007, subject to their own, separate Workers Registration Scheme and no longer have to rely on the Association Agreements between the European Union and their countries. Your other rights, including rights to work in self-employment in the UK, are as for other EU nationals, although be aware that some these rights depend on the EU national working, rather than just being, in the UK.
Nationals of Turkey benefit from European Community Association Agreements (ECAA) between the European Union and their country.