I'm a math undergraduate and I'm about to finish my second year at UCL. It's time to consider my graduate school, and I have some questions about it. In the UK, many universities provide math PhD directly after 3-year-undergrad, and they provide MSc for undergraduates as well.


Take Oxford as an example. It says that you don't need to have any publication before the doctoral programme and that you can apply it with a First-honour degree. But I wonder is it really possible to apply for a PhD without a master degree? Personally, I view MSc as a preparation course for a PhD. Therefore I want to know, is MSc a prerequisite for PhD, and if not, how it is possible that a 3-year student is able to do research with other 4-year-students?



Applying Phd directly after undergraduate
These sorts of questions are really best asked of a trusted advisor, who knows your skill level, life goals, etc. That said, I think Zhen Lin gives a great answer in the comments, that you should do 4 years of university studies before starting a PhD in the UK. If your goal is to be a professor, it's not wise to enter the PhD program until you are really prepared for it, because you only have those 3 years to do enough research to get your first job, and you wouldn't want to lose the first year studying things you could have learned in MSc or MSci.


For comparison, in the US, most PhD programs are 5 years, with an option to extend to 6. But, it's not required to have a master's degree before you start (and some offer a master's degree along the way). So, a "normal" path might be 4 years of undergrad followed by 5 years of PhD.


Even if you are talented enough to complete a good PhD on 3 years of undergraduate then 3 years of PhD, imagine how much stronger your PhD thesis would be with an extra year. You want to exit your PhD thesis in the strongest position possible, because the academic job market is tough. If you are not interested in the academic job market, then you probably don't need a PhD. Again, this is a conversation you should have with a professor you trust and get along with at your university.


