UK and "Rest of Europe", got to love this point of view :-) You might as well go ahead and say "UK" and "Europe", wouldn't be too far off the mark.
1. http://en.wikipedia.org/wiki/Berlin_Wall
2. http://en.wikipedia.org/wiki/Visegrád_group
3. http://upload.wikimedia.org/wikipedia/commons/3/39/Europe_po...
There has been a long history of splitting Europe into East/West, starting with when the Roman Empire was split into East & West. Though the definition of what's east and what's west has changed since then.