"This is the UK, isn't it? I was told by colleagues in the UK that those who do the best at university go into public service."
It certainly used to be the case, but the prestige associated with fast track civil service entry (almost like an officer corp for public servants) has fallen so far behind on pay that young bright graduates would rather work for the large multinationals than the lower paying government.
One of the few better things the Labour goverment has started to do is bring in managers from the private sector on fixed term contracts to run large government projects and initiatives. It has bust the public sector pay scale - but you get what you pay for.
Admin grades in the government - as per all over the world - are numbskulls.
Thanks for the clarification!