A2 Nationals
Nationals of Romania and Bulgaria, the most recent members of the European Union, are 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 EEA nationals, although be aware that some these rights depend on the EEA national working, rather than just being, in the UK.
A registration certificate is a document issued to EEA nationals that confirms that person's right of residence under European law. You are not required to have a registration certificate to enter, live or work in the United Kingdom. If you are a national of Bulgaria or Romania you are not eligible to apply for a registration certificate until you have completed 12 months continuous employment in the United Kingdom.
Family members who are not themselves nationals of an EEA country and who are in the United Kingdom with a national of Bulgaria or Romania are not eligible to apply for a residence card until the national of those countries has been employed continuously in the United Kingdom for 12 months. Until the 12 months is completed, a family member who is not an EEA national can apply for a family member residence stamp to confirm his/her right of residence under European law.
