More than three years into the Syrian conflict, 9.3 million people are in urgent need of humanitarian assistance; 3.5 million are in so called "hard to reach" areas. The UN and other humanitarian agencies have long argued that many hundreds of thousands can only be reached effectively from neighbouring countries such as Turkey and Jordan. But the Syrian government continues to refuse consent for "cross-border" operations of this kind despite a clear UN security council demand that it do so. Blatant disregard for the most basic rules of international humanitarian law by the Syrian government and elements of the opposition is causing millions to suffer. But this appalling situation has been compounded by what we deem to be an overly cautious interpretation of international humanitarian law, which has held UN agencies back from delivering humanitarian aid across borders for fear that some member states will find them unlawful.