The different ways of studying for a doctorate are: a PhD, a professional doctorate, or a doctorate through published work. You need to be aware that currently, the National Institute for Health Research will only award post-doctoral fellowships to people who have attained their doctorate through a PhD. Therefore, if you are likely to want to apply for NIHR post-doctoral funding in future, it is safest to study a PhD.
The usual requirement is a good first degree, which might be defined as a first class honours degree or a 2:1, or a masters qualification. To be awarded with a doctorate, you must have made an original contribution to the body of knowledge in your field. Therefore, your research question must address a gap in the literature in some way. Following registration of your proposal, your doctoral study will be expected to finish in three years (full-time PhD), five years (professional doctorate) and around five years for a part-time PhD. So, make sure that you choose a topic that is likely to keep your interest over this sustained study period and remain current and relevant to the field.
All institutions will offer you a supervisory team, usually a Director of Studies (lead supervisor) and a second supervisor, who you meet with regularly over the course of your studies. The supervisory team will usually have expertise in your topic area and the methodology you are using. Some institutions offer doctoral support groups for students and key research skills training, to help you develop your skills as a researcher during your doctoral study, in line with the 'Researcher Development Framework'. Visit here for more information
After submitting your final written thesis, you attend a viva where you will defend your thesis to examiners, who will have read your thesis and will question you about it. There is usually an internal examiner, from your study institution, and an external examiner, who will be an expert in your topic and from a different institution. The decision will be: Award with no revision (very rare), Award with minor revisions (usually up to 3 months to revise), Award with major revisions (usually up to a year to revise) or Fail (very rare). If you are studying for a PhD, an MPhil can be awarded as an alternative in some instances.