The Open Guide to London: the free London guide

At least according to tube stop names, Earl's Court has an apostrophe, but [Barons Court]? doesn't. Apparently, the latter probably had an apostrophe at one point, but it got lost:

http://www.linguistlist.org/~ask-ling/archive-most-recent/msg04651.html

And let's not even think about St James's Park ...