I recently attended an interview, where I was told that the school had hired someone to teach one person Mongolian. Yet, I was told that there wasn't the demand to justify offering Further Maths. This is usually the excuse given, but I'm sure most schools would have a few takers each year. I strongly suspect that it's more a case of teachers who can't or don't want to teach all the topics this would entail. IB Further Maths has a wonderful set of topics that give students some taste of what they can expect if they take a maths degree, so it seems very reprehensible that most students are never given the opportunity to study this.