13 minutes ago Chris Mason Political editor Getty Images At the heart of the arguments that rage around immigration and asylum are two of the most potent ideas in politics: fairness and control. A perceived absence of either, let alone both, is potentially toxic and particularly so around issues as salient and often divisive as how many people, and who, should be invited to live here and remain here - and on what basis. A tracker poll by YouGov suggests that immigration and asylum have been seen by many over the last 15 years as among the most important issues facing the country, alongside the economy and the health service. Think about that: in that time we have had the Brexit referendum and the Conservatives, Liberal Democrats and Labour in government at Westminster. In other words, while plenty, outwardly, has changed, there has been a stickiness to the electorate's concern about these issues and, it seems reasonable to deduce, a persistent sense of governments, plural, failing to grip them.…