I have seen on a couple of occasions caucasian crew operating on the LHR route as part of an overall LHR based crew. When I first flew on an LHR flight that was operated by an LHR crew, I found it very strange as even the Chinese crew, had thick British accents! I soon got used to it though! Of course you often hear FAs with Canadian/US accents on the N.American flights too

One time (years ago) was a male, who I saw on a number of flights, and more recently there were 2 female caucasians working CX250 in June 2011.

It was very strange to see caucasians and they were fully British, accents and all, but as you would come to expect their service was just as good/hard working as their Asian colleagues. I am not sure if they had some type of Asian language skill, I only ever heard them speaking English, but I know it is a requirement to have a second language which must be Asian.