Any disadvantages of having a PhD supervisor who is working only part-time at the institution? I have recently been offered to pursue a PhD in my field of interest.

Before starting the application, my future supervisor told me that he will soon be working only part time for my current institution (in the UK) while he will also be working in another institution in his home country (in France). He then added that if I see any problems with that and I would prefer finding another full-time supervisor, he would understand it. He also added that I would be the only PhD student he will be supervising during that time.

Actually, I can't really see any problems with the fact that my supervisor is working part-time at the institution but I obviously lack the relevant knowledge and experience on the PhD process.

So my question: Are there any disadvantages of having a PhD supervisor who is working only part-time at the research institution?
The most important at this stage is to obtain as many guarantees as possible in writing:


from the academic 
from the head of department
from the local graduate school


Essentially, academics are meant to dedicate a proportion of their employed time for supervisory duties, so that all academics have supervision workload fairly spread across a whole department, also variegated depending on the role of the academics (lecturer, reader, professor).

If the academic is employed in the UK higher education institution for 50% full-time equivalent, then their supervisory duty should be halved by comparison with colleagues.

If he said that you will be 'that I would be the only PhD student he will be supervising during that time', that's probably what's behind the statement.

However, it does no harm to have this employment arrangement confirmed by the head of department and the local graduate school who ultimately have to agree to such arrangement. So you can make sure the academic understood well.

As Captain Emacs points out, then, there is a lot that boils down to your own expectations and needs in terms of supervision. There are bound to be pros and cons. Simple basic question: is the academic very IT-literate or does he do everything from print-outs? If he's constantly travelling between job places, that might become inconvenient when drafts need careful attention in a reasonable turnaround period.

The more you discuss and nails the practicalities of the relationship at an early stage, the less likely it is going to go bad.

Last but not least, if you get funded with a local scholarship or a grant from one of the big funding councils and charities, your supervision is more likely to be successful, because the funding set up will create an additional level of accountability for both you and supervisor.