Any national of a member state has a right to live, work and set up business in any other member state. However, in most member states certain professions are regulated. A migrant wishing to become established in the UK and pursue a regulated profession must have his qualifications recognised by the competent authority that allows access to the profession. The competent authority will provide the migrant with the appropriate documentation.
If the profession is not regulated, there is no official requirement for further documentation relating to the qualification, and an employer would decide whether the migrant's qualifications were acceptable.