I'm quite surprised that this hasn't been brought up here, actually...

Anyway: http://news.bbc.co.uk/2/hi/uk_news/politics/6906481.stm

Russia has expelled 4 british diplomats, as a response to getting their own diplomats expelled.

Any thoughts on what is happening? Or what will come? Is this just a casual thing, or is it the beginning of a major diplomatic situation?