Quite frankly I am staggered and depressed by some of the experiences on this thread. Due to the robust application, supervision, training and review processes now demanded by all of the major research councils, it is now without question every University's duty to offer adequate and ongoing support and advice throughout the lifetime of a research student's project. Any supervisor worth their salt will spot flaws and weaknesses as the project takes shape so that, thankfully, failing a PhD at the very final hurdle - by offering an unsound thesis - is now becoming almost unheard of. While this is cold comfort to some of the writers here - and I am personally angered by your own experiences - I would argue strongly that only bad supervision will lead to a disappointing outcome - even the most stubborn external examiner will be drawn to pass a thesis that is clearly of the correct standard.

So for all you continuing PhD students out there - demand only the highest levels of attention from your supervisory team - you are not expected to work in isolation without rigorous feedback - , and if all else fails, change your supervisor - most universities will allow this nowadays.