Win or lose, Corbyn will set the agenda unless Labour speaks up

How do you win a political argument that you seem to have been losing for a long time? Some in the Labour party are quite keen to know the answer, given their membership may be about to elect as leader a man so far on its fringes that he only occasionally obeys the party’s whip. And while he may be the last person Labourites would like to listen to, David Cameron knows a thing or two about this, having spent the last five years as Prime Minister trying to fight a recalcitrant group of backbenchers who were always demanding he go further than he planned on immigration and Europe.