He's effectively scuppered Labour's chances of winning in 2020, if he's still leading the party then. Firstly, most of the electorate aren't hard left socialists, so a lot of his views will be anathema to them. No way are they going to go for a man who wants to scrap our nuclear deterrent and leave NATO...who consistently supports terrorists (apparently, he doesn't understand why we're sending drones to kill murderous fascist traitors who wish nothing but harm to this country) and who wants to invite more refugees to our shores.
Talking of which...his first action after being voted leader was to go to a "We welcome the refugees" rally. Got his priorities right there, then.