Not just the middle east, there is a wide variety of cultures in central London. I think less than 10% of people I overheard speaking were using English.
London was fun, but hell I wouldn't want to live there/work there. Far too busy for me. Hyde Park was nice though.
Knightsbridge in general attracts a lot of arabs from the UAE, Kuwait etc. Some of them when they visit London only stay in the Knightsbridge area. My wife works for a luxury brand and deals with some wealthy arabs that don't even know anywhere outside of Knightsbridge.