PhD Funding.

Well, we might as well stick to your subject first. Engineering PhD students can expect between £14 - 16k per year as a tax free stipend, they are amongst the highest paid students in the UK and funding is pretty much guarenteed if you have been accepted onto a PhD programme. Science PhDs get slightly less, but they too are generally guarenteed funding if accepted onto the programme. Arts, humanities and social sciences are different in that funding is competitive itself as well as entry onto programmes at institutions.

I know it's a vague question and highly dependent on many factors, but what would your best guess be at how much of that would be swallowed by research costs?

None, that's your stipend. Your tuition fees are paid, research costs are covered by your supervisor's grant.

ChemistBoy's got it all there. Engineers, Biochemists (in charity funded places) and Vets all seem to get the most money for PhDs. I've seen PhD stipends of £21,000 (tax exempt) before. Most subjects get their PhDs from only one research council which only have one or two rates, one for outside London, one for inside. You usually get about £2k more per year if you're in London.

Your stipend is how much you get to live off, think of it as a salary but without having to pay tax on it. Your tuition fees will usually be paid for you out of other funds by the research council. Most research councils will also supply your department with some extra funding to cover equipment and money for going to conferences etc.

The stipends are actually worth a lot more than the values imply since they're exempt from tax and you get benefits such as student discount everywhere, exemption from council tax etc. As an example, a stipend of £14,000 is equal to a salary of about £17,700 before any council tax and student discounts benefits. You know, something else that might become more important in the next year or so is that once you're signed up to a PhD, as long as you do the work and pass your yearly reviews then your funding should be secure for the duration - unlike some jobs in the current financial climate. :s

Why isn't "Dr." the new "Mr."?

Also you need to come up with something vaguely original which most people would find the most difficulty in.

Not in the sciences, you just tag along with someone else's original idea.

Why am I a social scientist again?

None, that's your stipend. Your tuition fees are paid, research costs are covered by your supervisor's grant.

Here's an interesting question then...

The income threshold for the Student Loans Company before you start having to pay back your Student Loan is £15,000. So were I to get a PhD stipend of £15,000 and upwards (as you said is common for Engineering), then would I be expected to start paying back my student loan?