Mass killings and millions forced to flee for their lives have made Sudan the "epicentre of suffering in the world", according to the UN's humanitarian affairs chief. About 12 million people are believed to have been displaced and at least 40,000 killed in the civil war - but aid groups say the true death toll could be far greater. Tom Fletcher, the UN's under-secretary-general for humanitarian affairs, told Sky's The World With Yalda Hakim the situation was "horrifying". "It's utterly grim