Katy is B/C-List in the UK.
Album is bombing compared to everywhere else that's English-speaking in the world (was in the low 30s until a £0.99 discount last week), tour is nowhere near sold-out, Unconditionally bombed despite a performance on the X Factor finals/other major TV shows, Dark Horse's sells aren't much to brag about either (Silver certification right now).
Rihanna and eBey are the only foreign girls making any impact. White girls can't succeed in a post-Emeli Sandé world.
Oh and don't get it twisted, there's plenty of tickets left in Londres:
here or via the O2's own booking providers. Entire rows still available, in fact. Nothing in the UK is sold-out and it's touch and go as to whether they actually will sell or not without Groupon, competitions, reducing the capacities etc.
It must be a hardcore show 
