Probably unelectable but a very admirable man nonetheless. A long-standing critic of racial injustice and bigotry, he held positions that, at the time, were seen as not only outlandish, but very controversial (his stance on LGBT rights and The Troubles comes to mind). Time and time again, he has shown compassion for the most vulnerable in society, and vehemently fought against a reduction in tax credit allowance/further benefit cap decreases without parlimentary consultation while the other contenders for the leadership position abstained, despite widespread opposition from the base of the Labour Party. This, of course, isn't to say he is without faults

Foreign policy is one area which clearly has to be refined for a general election, but his economic policies aren't too controversial (i'm personally skeptical about alternative QE plans but aside form that, there is nothing too radical). The majority of the British public – including the majority of Conservative voters – support nationalising rail companies , most people support easing of the austerity program or ending it completely, and the Labour Economic Advisory Committee (formed by Corbyn) is composed of highly qualified economists. The issues arising from his stance on NATO, the Falklands, and Trident point to the fact that he obviously needs to refine much of his foreign policy but I do think he has a popular economic message that could, conceivably, resonate with voters, even more so now considering the incompetence of the Tories. I would argue this is probably one of the reasons why Labour is now polling ahead of the Conservatives.