Nothing. The truth is that dating back to the 50's through the today, villians reflect the current political or news agenda. During the Cold War, you got a lot of Russian/Soviets as villians. Now you get lots of people from desert countries. In the beginning the government used television and movies as a way to show that we would 'symbolically' triumph over the other 'bad' country. Propoganda.
Now, movie makers have found it worked as a way to bring movie watchers together and make the good guy more sympathetic. You rooted harder for him if he was fighting the guy from the country getting all the current bad press. Riding on the wave of pro or con idea rampaging through the media at the time.
I haven't seen many British villians lately. But if you are seeing it, it could be a reaction to the revamping of the James Bond and other 'spy' story lines. James always had a very British feel. Perhaps this is a backlash.