Earl's Court or Earls Court? Which is the correct punctuation for this area of west London?
It's a disagreement which can't be settled locally. TfL uses an apostrophe in the name of the tube station:
While just across the road, the now-demolished exhibition centre avoided the use of the apostrophe:
To work out which is historically and grammatically accurate, we need to look at the history of the area. For 500 years, the whole area (around 711 acres) was owned by the De Vere family as part of the Manor of Kensington, who passed the title of Earl of Oxford down through the generations. By this reckoning, Earl's Court is the court belonging to the Earls, and therefore the apostrophe is justified.
What about Barons Court?
Although TfL spells Earl's Court with an apostrophe, nearby Barons Court is spelled without. It's thought that the name Barons Court comes from the Baronscourt (or Barenscourt) estate in Ireland.
William Palliser, an Irish politician, was involved in developing the Barons Court area in London, and he named it after his home roots. He also gave his name to Palliser Road, which runs right up to the station.
In this case, the Court in question doesn't belong to any particular baron, so Barons Court without the apostrophe is correct (of course, we could go back further and find out where the Irish Baronscourt got its name, but as that strays outside of the M25, we'll leave it there). Even more correct in this case would be Baronscourt as one word, as this is how the name of the Irish estate was written.