Factors considered in UKphd applications ??

[v2gls]

Does anyone have any experience on how universities assess phd applicants??
Which of the following would be a more reasonable choice so to pursue a phd in a top10 UK univ??
On the one hand, i could do my master degree there ( but apply only after 3-4 months from the beginning of master),
while on the other hand i could attend a strong nonUK programme and apply during the 2nd year of my master
(so the university will be able to assess me based on more facts)..

What else should i bear in mind?? Any thoughts or advise would be very usefull..