I'd agree with bilbobaggins about it creating a very poor perception. It would be a red flag on your cv. I think it's unlikely anyway if you were honest about being near completion that the university would award you funds to do a second PhD (I imagine if it's research council money and you've already had some that it might be forbidden anyway). Why not write to this university (and any others nearby) with a copy of your cv and ask whether you could be considered for any hourly paid teaching next academic year to bridge the gap? But seriously if you are going to be confined to one geographical area for the foreseeable future, given the way things are looking job-wise for the next few years across academia, start working on a plan B for an alternative career in case this doesn't work out. That new ESRC scheme will be much more competitive than the postdoc fellowships were as there will be fewer of them.

Don't panic. I hit a similar snag and ended up having a meltdown in front of my supervisor, who gently pointed out that the flaws in my work were always going to be much more obvious to me than to anyone else. My suggestion would be to skate over it as best you can in the chapter, but to consider including the issue/concept/theorist/new research question in the conclusion as a fruitful angle for further research. If you can find a review article of the theorist's work you could also stick a footnote in saying see x for a fuller discussion of this point. Then when you've submitted do some reading and get a more coherent account together of where this new theorist / concept connects with your thesis in case it comes up in your viva. Worst case scenario it's set as a correction in which case you've already done the work. Of course this will only work if your supervisor is prioritising submission over perfection.

I had a glossary with both acronyms and the odd highly technical term in my thesis. The external commented that he'd found it helpful as a quick reminder when reading it, but it has to be said, there were a LOT of uncommon acronyms in my thesis.

This is predominantly a UK-based forum (with some Aussies) and I suspect from how you phrased your query that you are talking about the US system. From a UK perspective the academic job market is going to get worse not better given our government's decision to slash spending on higher education, so there's nothing to be gained by delaying submitting. Plus we get a certain number of years funding and once that runs out, that's it.

as Chuff says just like any other workplace.... And just like in any workplace, when junior people start trying to meddle in office politics, particularly in the PhD situation those PhD students who wander round always criticising other students and staff but never taking responsibility for their own work, then it tends to end in tears for them. Staying clear of the politics if humanly possible, being pleasant to all and sundry and getting on with your own work in a professional manner seems to me the recipe for success for a PhD student just as it is in any workplace.

Two thoughts: while it's still fresh, write down as much as you can remember of their comments particularly regarding the impossibility of the topic. I hope for your sake that the examiners will have the guts to write a report that actually queries the supervision and viability of the topic, but in case they don't, your own notes would be helpful. I'd also collect together any annual progress reports or upgrade reports - any evidence basically that you were never warned that there were problems with the thesis. Then you need to read both the appeals and complaints procedures for your university - the more meticulously you follow these the better. Does your students union have any sort of advice centre - someone independent, who knows the system, might be helpful at this point to have a look at everything for you.
My gut feeling based on what you have written here, is that you may have difficulty successfully appealing this decision. A MPhil is after all a legitimate decision for the examiners to come to and you say the viva was professional and their criticisms constructive. You have to appeal usually on grounds of an improper examination or bias etc and it sounds like you might not have it. Usually, you cannot challenge the academic judgment of the examiners (but check the procedures). What I do think you have, again just on what you've written here, is a potentially very good basis for a complaint against the university and so a potential case for compensation for lost earnings etc.

I'm really sorry - that's the sort of news no-one needs and that sadly a lot of university employees are getting. Are you a member of UCU? If so, it might be worth talking to your union rep just to be sure that they are doing the redundancy procedure correctly given what you say about the basis for it.

You don't need an IR PhD to work for those organisations, it won't be held against you but it won't be a particular advantage. Honestly given your career goals, unless you are offered a full scholarship and really want to spend 3-4 years working on a specific topic, I would say no.

I think not having the PhD in hand will be an easy reason to reject you at the moment. Given the sheer numbers of applications, if there's anything to say in the advert that they expect a completed PhD, then I think that they might just sift out those without one straightaway. I have two other thoughts, both of which are a bit difficult to phrase, so apologies if they come across as tactless. I'm assuming from what you say about college committees that you are probably at Oxford or Cambridge - if not what follows is irrelevant. If so,
1) if you are applying for Oxbridge postdocs, I wonder whether your supervisor can do some investigation on your behalf i.e. are they keener on appointing outsiders than insiders, are you not viewed as 'the most promising' in your cohort, is it because everyone hates your supervisor and any student of his/her is tainted by association. I don't know whether this is sour grapes on his part, but I know someone with an Oxbridge soc sci phD and he reckoned that there was an unofficial decision at departmental level about who they wanted to keep and if you weren't on that list, then as an insider there was no point applying.
2) If you are applying outside, could you get someone who hasn't been to Oxbridge to look through your applications to make sure it makes sense to outsiders (given the different terminology for all things Oxbridge related) - and fits the expectations of other universities e.g. your publications and future research plans are such that it's clear you understand REF expectations. That seemed to be something letting down this friend of mine - he said he'd been given very little guidance and particularly hadn't understood how different the teaching environment and expectations were elsewhere.

Is your current MA recognised by the ESRC as providing sufficient research methods training? If so, you don't need to do a special research methods course. If not, then if you want ESRC funding then you have to do one but I'd definitely suggest having a go for 1 + 3 funding this year. Reasons 1) if you don't get it then at least you are no worse off and could still self-fund the second MA - it just adds another option and 2) the experience of putting the application together is invaluable and would give you a head start if you had to reapply for +3 the year after. The universities don't care if it's 1+3 or +3 as they're not funding it, the ESRC is, so I think you are wrong to worry about that being a factor.
Your 2:2 is never going to help matters and won't go away however many masters you do. The ESRC is very keen on quantitative studies though, so if that's what you're thinking of, you could flag up the quants in your u/g degree in the application and highlight any relevant stronger marks - that might help. It's more likely to be a reason for rejection if you have to go through the open competition rather than getting a quota award, so I'd target universities with quota awards (i.e. the funded places where the university not the ESRC picks who gets it). That said, as you may have been told, the whole funding system is changing this year to a system of doctoral training centres, and the ESRC haven't announced the results yet, so universities won't know yet what they do or don't have to offer, so if you get evasive replies, it's probably because they don't know rather than your application.

I have heard that the course at Sussex is very well respected by practitioners. I would ask the departments for information on employment prospects and whether they could put you in touch with any Indian alumni who could tell you how it worked for them. It might also be worth looking at the staff list to see whether there's any evidence of people with Indian experience, as I would think given your aims, that it would be very helpful to have someone like that around to supervise your dissertation for instance or for contacts for your job search.

What are the entry requirements? I'd have thought your honours degree plus your nursing qualification would have more than sufficed? Do they need something extra eg chemistry or something? I'd just ring up admissions and ask if your qualifications are sufficient - they'll be used to questions like that.

What have you done to make contact with social scientists at your institution? Presumably if you are this unhappy then it will have come up as an issue at your upgrade and annual reviews? Have you followed up extra methods training courses etc? Would that give you some contacts that you could talk to regarding methodology or theory questions to make you feel more secure? (Bearing in mind that people will normally want to clear this with your supervisor to avoid treading on toes).
Unfortunately, if you are not willing to make a proper complaint then the university is unlikely to do anything. From their perspective, you did agree to start a PhD in a different field with no-one really able to supervise the topic, so in some ways, particularly if you've let it go this long, then they are going to assume things are OK unless you really tell them they are not. Is the relationship with your supervisor now irrepairable? I appreciate from your OP that you dislike her and have little respect for her - are the feelings mutual? If so, then you've nothing to lose - you presumably aren't looking to work in this field but in your social science one, so there would seem to be less danger in burning bridges than usual.

You might want to check the rules of your university and the funding body. Some insist that only people with permanent posts can be named as grant holders.