The choice of research topic is up to you but must be worked out in consultation with your supervisors. It is a good idea to enter into discussions about your research project with the Department's Director of Postgraduate Research, Professor Roland Axtmann (firstname.lastname@example.org), before drawing up an initial proposal and starting the application process.
However, all good topics develop over the course of your reading and supervisions, and it is likely that you will only slowly gain a clear idea of where you are heading. At the end of your first nine months you present a chapter of about 10,000 words, a synopsis of your thesis, bibliography and table of contents, plus a list of training courses you attended to a progression panel which makes recommendations for your future direction. Thereafter you should expect to work on individual chapters (four or five is a typical number), including an introduction and literature review.