<p>The UK system is based pretty much entirely on academic record - basically the grades achieved in sets of external exams we sit at 16 (GCSE), 17 (AS level) 18 (A level). Applicants applying during their final school year will be given offers conditional on them achieving certain grades in their final exams. Consideration of legacy status is non-existent, ditto sporting ability.
ECs really matter only for the professional degrees eg medicine, dentistry, teaching, social work, health care etc, where some relevant experience is essential. Otherwise it’s a nice, but unimportant, paragraph at the end of your personal statement showing you have some interests preferably relevant to the course you’ve chosen.
We are allowed to offer lower grades to applicants from poorly performing schools and areas with historically low levels of university participation (and children leaving the care system). Most of the top universities have special programmes to try to encourage students in this category to apply and run summer schools etc to try and help them. But on the whole it’s pretty much 100% based on academic achievement.
It’s a very straightforward system compared to the US but it really comes down to a different idea of what a university education is about. I think both systems have advantages and disadvantages and will suit some better than others.</p>