The United Nations humanitarian chief, Martin Griffiths, has said that leaders in war-torn countries are prioritising political rivalries and power over the end of fighting. In an interview with the Associated Press, he added that humanitarian workers in conflict zones see the results of political failures in their everyday work. Griffiths comments come as reports say 200 relief workers have been killed in Gaza over the duration of the eighth-month conflict. One high-profile incident in April saw an Israeli strike killed seven workers from the charity World Central Kitchen who were delivering …