The full scale of Islamic State's influence can today be laid bare as it's revealed dozens of terror groups worldwide have pledged their allegiance to the barbaric extremists. From militia lurking in the jungles of the Philippines to sleeper cells training in the deserts of Libya, a vast array of groups are now claiming to be operating alongside the jihadis' notorious black and white banner. It is clear the groups have little in common except their desire to establish their own kingdoms governed by a traditional interpretation of Sharia law. But they are united by one other common principle -...