How much difference is there between a PhD fellow and a PhD candidate?

I've never heard of a PhD fellow. A PhD candidate is, I believe, someone who has passed their first year upgrade right? Not entirely sure.

Is it an official title or what they call themselves? If it is the former - pass, if the latter they might just be calling themselves that to blow smoke. I know a third-year student that calls himself a "PhD fellow" as well and he made the title up himself to make his LinkedIn sound better. After so many years of education, you sometimes want to drop the student moniker and at least pretend to be something else.

It annoys me when people do this. 'PhD fellow' sounds ridiculous and makes no sense, and I think the 'Candidate' title is irrelevant in a UK context as it's properly used in the US/Canadian context where you've passed all your exams and other requirements and are 'all but dissertation' (ABD). We're generally all ABD in the UK in that we start with the dissertation (research training requirements etc notwithstanding) so the 'candidate' distinction is pretty weak sauce, imo.

My approach is to suck it up, we're all students. This kind of transparent, vain posturing is one of my personal bugbears (and perhaps one of the reasons I'm not suited to academia). You can always say 'doctoral student' or perhaps 'PhD researcher' if you're determined to puff up your title but I don't understand the impulse. Well, I do understand it, but it really annoys me.

I'm happy for people to call themselves what they want as long as it vaguely describes them! I go with "PhD student" myself, though I do think "PhD candidate" sounds more prestigious (and technically as far as I understand that is the official term once you've passed the 1st year upgrade). I did go through a phase of being "PhD researcher", as I thought it would increase my credibility when I was trying to get into schools to do research. I don't think it made any difference!

Given that the PhD is not really like being a student at all, there isn't a good term.
I used PhD Student but it didnt feel like a good description.
Using PhD Fellow is absolutely ridiculous. Anyone doing that around me would have had the piss taken out of them mercilessly until they stopped it. PhD candidate doesnt make sense at all to me. Candidate for what?

PhD candidate = A candidate (on the program) for (being awarded) a doctorate.

PhD student is nice because most people instantly get what you mean (although they probably still have no clue what it entails). Oh, so you're a PhD student...

OK to me candidate sounds a bit passive in that sense.
Student sounds more pro active.