I had a online meeting (30min) with potential supervisor and another professor in the department. They asked details about my research plan and feasibility, and etc.. You need to prepare to answer to detailed questions
I interviewed at University of Cambridge (Cambridge, East of England, England)
Interview
Very easy, just a casual chat with the prof.
Asked me about my experience and what I want to do.
Asked what papers from the lab I had read.
Asked about funding I'd applied for.
30 minutes interview with standard questions such as motivation and your future plan. Good to read few academic papers that are relevant and not relevant to your field. Be prepared to talk about it.