GN amassed huge viewing figures for his Channel 4 show, so the BBC decided to pach him, which it did, for a massive fee.
Of course, they conveniently forgot that his forte is inuendo of a style which is allowed far more largesse on a commercial than it is on the BBC, which has to answer to its licence payers, and provides an entirely different set of programes, for a different audience.
Now Norton has become the BBC's white elephant. They can't afford not to use him, they paid too much to stop Channel 4 having him (which is not quite the same as actually wanting him for themselves) and now they are stuck with him.
Since his arrival, Norton has lurched from one dire format to another, remaining resolutely one-dimensional and largely un-entertaining. For some rerason, the BBC has decided that 'variety' should be given as mass entertainment? Why? If it worked, ITV would already be doing it - they aren't ... because it doesn't! Tastes are far more sophisticated these days, you might as well stop giving kids i-Pods and offer them chemistry sets instead.
You wonder how on earth an organisation with the financial resources, and cultural history of the BBC could get it so horribly, and expensively wrong, but then one word comes to mind .....DAVINA.