Please outline your career aspirations and why you would like to be considered this
Research Studentship?

How should one answer the above question. Please give an example if possible.

Questions like this are not tricks, the interviewer simply wants to see if you have thought clearly about why you want to do a PhD in general and this one in particular. Your career aspirations may be to work in university research, become a lecturer, work in industrial research, etc. University research is a truly international career and you may say you'd like the opportunity to work overseas. A bad answer would be that you're not yet sure of your career options and thought doing a PhD might be something to do in the mean time.

When talking about the particular project, don't feel like you need to say something like "I've been interested in the haemoglobin oxygen binding sites since I was a child" - talk about the bigger picture - "I'm interested in the causes and control of anaemia" might be a better starting point.

In reality if you really cant answer this question then you should not be considering doing the PhD until you are sure what to expect both before and after. However if you are sure then how about getting the question in first - i.e. What career opportunities can I expect after this PhD?? - where do you see this leading to in the future?? etc.... make them sell it to you - thus making it look like youve thought about it seriously!