Quote From sneaks:
personally I think providing a PhD by publication i.e. 3 good quality journal articles should be the new standard, as then its peer reviewed and you have practiced actually being a researcher, like you will for the rest of an academic career. I'll NEVER write a thesis again (Please please I don't want to!!!)
Couldn't agree more with Sneaks here. There are so many benefits for the PhD candidate walking into a VIVA with a significant section of the thesis already published. As one academic said to me, as an examiner in a VIVA how can he truly criticise a piece of work (say a chapter) that has been blind peer reviewed twice and published. Of course there might be discussion on why the student chose a certain approach over others, but at the end of the day it has been published and that's that. It's of publishable standard and has made an original contribution to the field.
I actually do think that a certain number of publications should be required before the Viva. In my experience my publications have come through conference participation. I attend a lot more European than UK conferences and in Europe 8 times out of 10 the conference will be connected to a planned publication - not simply a publication of papers but as part of a special edition of an academic journal. I've found that presenting part of my research has so many benefits - I'm reconnecting with material I might have written a year ago and subsequently have to rewrite it for the format of a 15 min talk. Each time I've found it a form of concentrating the main arguments and have reinserted the much more focused writing back into the thesis. It's a great form of revision and rewriting.
Even submitting your work to good journals has certain benefits. Even if you don't agree with the reviewers comments, you are getting feedback on your work - probably at a quicker rate than from your sup!
I don't think I'm being overly ambitious aiming for 3 publications before my Viva. I'm nowhere near an oxbridge standard student. I'm basically just an honest slogger but I believe in getting my stuff out there. As Woody Allen said, 80% of success is showing up.