Here it is:
"Since the early 1950s, the station name has been spelled with an apostrophe on the tube map although the name of the local area is generally spelled without. Prior to the 1950s tube and rail maps show the station name without the apostrophe and on the station buildings the name has variously appeared with and without the apostrophe. The name of the local area has always been shown with an apostrophe on Ordnance Survey maps, and also by A-Z, but other mapmakers do not use one.
There is an acknowledged reason why the apostrophe is used for Earl's Court station but not for the nearby Barons Court. William Palliser developed the Barons Court estate. A book in the Society of Genealogists, annotated in pencil by R. Burnet Morris who knew Sir William personally, provides a history of the area. Morris declared Barons Court was named "after Sir William's Irish Estates," Baronscourt. As a result, unlike its neighbouring station, Earl's Court is written with an apostrophe."
End of wikipedia paragraph
Notes from me:
1. Ordnance Survey use an apostrophe, 'other mapmakers' don't! (ie mapmakers have no rule on the matter, of if they do, they don't know the f. what it is.)
2.Prior to the 1950s - no apostrophe! (ie history is not on the side of those who imagine that people used to get apostrophes right but when civilisation started going down the pan in the 1960s, it was a matter of greengrocers starting to get them wrong. )
3. On the station buildings the name has variously appeared with and without the apostrophe! (ie we can't rely on official signs for rules on which way the apostrophe should be used.)
4. The Barons Court Estate should, according to this, have been the Baronscourt Estate. But it isn't! So, it's neither correct or incorrect to write Barons Court Station. It's just any old ordinary bit of varying editing.
5. The mix of inconsistency, anxiety and arbitrariness make for a lethal cocktail when it comes to usage. People thrash about looking for rules and precedence on the use of the apostrophe but in many circumstances - as here - they're not to be found.
6. On that basis, it's my view that I don't think the apostrophe will last more than about 30 years.