Almost all the companies that are operating in US have their offices in London. Barclays, vodafone are the prime examples of UK based companies that are operating all over the world. So UK is no less in comparison to US.
As far as B schools are concerned the awareness about the European MBA programs is generally low outside the home country. The US schools have very active and well-funded marketing departments that work with the industry and media to promote themselves. Due to their close relationship with the industry, the acceptance level of US MBA graduates is also high.