THE next head of humanitarian affairs at the United Nations should be chosen on merit, not by horse-trading between Downing Street and the top floor of the UN’s Manhattan HQ. The opportunity to succeed Emergency Relief Coordinator Mark Lowcock is still (officially at least) open – submissions close on 15 March – but the betting in diplomatic circles is that his successor, yet again, will be a British name put forward by London.  Thanks to an arcane UN convention, humanitarian affairs at the UN is a British fiefdom. We’re hearing that even if he knows it looks bad, Secretary-General António…