It is acquired socially. The UK has a formalised class system dating back to the "divine right of kings". The "ruling elite" are rather literal as the membership of the upper house (House of Lords) is limited to hereditary peerage.
92 out of 813 seats are hereditary peers, the remainder are life peers [Edit: forgot the Bishops] appointed (technically) by the monarch on the advice of the government.
There's really no such thing as a class 'system', let alone anything one could point to as being 'formal'. There is a bunch of in/out group signalling with fairly extreme geographic variations. Mobility across social boundaries can be achieved by understanding and adapting to the signalling although crucially (and getting back on topic) this requires the belief that you are entitled to do so.
I'm down on the notion of class in general personally. I think it's at best an incredibly lazy intellectual model of complex social phenomena. Basically I think there's no such thing [0], but I do very much enjoy listening to the things people say while they're explaining why I'm wrong about this.
[0] Problematic for this theory is that people certainly believe there is and this has operational effects.
It is acquired socially. The UK has a formalised class system dating back to the "divine right of kings". The "ruling elite" are rather literal as the membership of the upper house (House of Lords) is limited to hereditary peerage.