A few British universities did have candidacy. There was a financial penalty from the research council if a certain percentage of your students didn't finish in 3 or 4 years - so the university would make everyone a candidate and only count them as a PhD student for the stats once it looked like they would do OK. Eventually this evolved to being a candidate right up to when you submitted so there was a 100% completion rate but the research councils wised up to the scam.
