London | World Trade Organisation (WTO) director general Roberto Azevêdo has unexpectedly quit his post a year early, creating a leadership vacuum at the embattled global umpire in the midst of a global economic meltdown and rising trade tensions.

His departure will likely kick off a protracted and bitter struggle over who should next lead the WTO, as China and the US arm-wrestle for supremacy in the multilateral system while developing nations demand a non-Western candidate.