The government has pledged that a new generation of grammar schools will improve social mobility. One way being proposed to ensure that is to force grammar schools to lower the 11-plus pass mark for poorer children from disadvantaged backgrounds. The idea is already running into opposition. People are asking what's the point of having a selective academic system if you don't select the most able students? It's also said that it risks patronising disadvantaged communities by sending out a message that less is expected of them. At the heart of this debate is the moral value of meritocracy - that you should be rewarded on the basis of your skills and not on your background. Every child should be offered the chance to achieve their maximum educational potential, but what if they can't achieve that because of an accident of birth? Isn't it right to try to balance the scales? Or will that come at the cost of another, perhaps more able child, being denied a place at a grammar, again because of an accident of birth? Does this encourage identity politics and blur the line between equality of opportunity and equality of outcome? Is this treating the symptom and not the cause - creating a state education system that's lost sight of the quest for academic excellence and is more interested in the politics of social mobility, class envy and division? Witnesses are Dr Martin Stephen, Dame Rachel De Souza, Prof Peter Saunders and Conor Ryan.