London is important as a neutral build for England. A fleet in Edi is obviously heading for Germany (unless you're attacking Russia, which is stupid), and a fleet in Liv has nowhere to go but France. But a fleet in London? That's something else. When in doubt, build here.
England starts with a fleet in London. What this fleet does is crucial in determining the shape of the game.
If it opens to the North Sea, chances are England is attacking Germany or Russia. If it opens to the Channel, he's probably going after France.
Jack