Refugee law faces a serious crisis in Europe. This crisis highlights the need to explain the following questions: What is the relationship between refugee law and immigration policy? And how much immigration do States need to tolerate for moral and practical reasons even if they do not wish any immigration? The general legal principle of necessity offers a useful theoretical basis for refugee law. Necessity explains the conditions under which it would be unfair to fight off unwanted immigrants by deportation and punishment. Necessity also explains the conditions under which a restrictuve immigration policy is not feasible at a reasonable cost versus desperate individuals. It follows that necessity overrules a restrictive immigration policy and qualifies as a robust explanation of the purpose of fair refugee policy. This study explores the consequences of the theory of necessity for the interpretation of key concepts of refugee law (persecution, well-founded fear, reasons of persecution, asylum) and concludes that a generous refugee practice can be conceived and logically justified even if a restrictive immigration policy is a political reality.