The postwar British economy under Labour's Welfare State reconstruction was based on a variant of a worker-corporate/State accord that was a familiar pattern throughout the West. The British model is this: there will be public services available to the population (health, education, housing) paid for by the State, which will employ a sizeable percentage of the population. In return for the security of housing, education, and health services, the population will accept lower wages.
Until recently, professional education in medicine, law, and other academic fields was free and many students received a stipend from the State. The thinking was that if the State paid for your education, then your salary would be lower than what it might be in places like the US, where education is not free.
This system has held up pretty well until the last ten years or so, when there's been a disequilibrium between living costs and salaries. But to answer your question about employer's greed. The answer is no, for two reasons.
Firstly, as explained above, the postwar system wasn't meant to pay high salaries to professionals. Frankly I don't believe that professionals, legal, medical, or educational should receive any more, if not, in fact, less than sanitation workers or hospital orderlies. The benefit of a professional job is that one has more freedom for creative thought and self-management in the workplace. That's a freedom that one shouldn't then be over-compensated. Why should someon who went to law school deserve a better salary than someone who did not? Personally, I think that it's right that you should earn as much serving pizzas, since that's a less creative post, although certainly one that provides a greater benefit to society than being a non-public interest lawyer.
Secondly, the British system places a high barrier to adjudication as it allows the winner in a civil suit to demand their legal fees from the loser. This has meant that the British courts haven't become the casinos that they are in the US. Hence the lower salaries for a law profession, since lawyers income isn't based on speculative redress to the courts.
The benefit of living in London is that it isn't a society that is willing to allow as great a freedom for unfettered pursuit of market individuality as the US. That's ultimately the choice one has to make: society or the self.