Whilst this thread has been highly quality entertainment, I would like pick up the following.
Golf is very much a Scottish sport, not English.
And if you want to argue semantics, Boxing itself has been around for a few thousand years, very much not invented in England, though I will grant you the modern version does have its base in England.
Rugby and Cricket? Yup English sports, I'll give you that. But, uhh, shall we take a quick whistle stop tour of some of the major players of these sports on the world stage? In Cricket we've got Australia, New Zealand, South Africa, India, Pakistan, Sri Lanka and the West Indies... hrm... what do these have in common? Ah yes, they were all ruled by us for a couple of centuries so the love of this sport has hardly grown organically. Let's think about countries that have a huge cricket following that weren't part of the Empire... and we're done.
As for Rugby, basically the same as above, except that you can say that it is popular in some other areas of the world that were not part of the Empire, like France, Italy, Argentina.
So yeah. England. Sporting capital of the world, clearly.