How different is British English from English cultured in rest of the world

The differences are mostly in accent, pronunciation and spelling and there are some idiomatic and vocabulary differences, too. I believe that Indian English tends to follow the British spelling conventions (e.g. '-our' instead of '-or', '-ise' instead of '-ize', '-re' instead of '-er' in words like theatre, litre and metre) while English in the Philippines tends to follow the American conventions. The grammar and syntax are virtually identical in all versions of standard English and, at least in the written language, all versions are mutually intelligible.

Indian English is much closer to British English - thank goodness!