Corbyn is an odd case in that he has the support of a huge number of Labour members and their non-member supporters, but almost none among the Labour MPs and the previous Shadow Cabinet or the pro-Labour media. His victory in the party election was very much a blow to the established Labour leadership and their ideology, and also a blow to the right wing parties of Britain in general since it opens up the possibility of a very different political landscape they would have to campaign in.
For about 20-25 years now all the major parties have had the same fundamental ideology and little variation in their policies. A Socialist being elected to lead the opposition party is quite a turn of events and is drawing as much attention as the SNP rise did, though with just as much if not more mudslinging being done by the news companies and political figures that benefited from the status quo that is at risk.
Corbyn is counter to the agendas of most of the British media, a lot of the Labour party's (former) leadership, the incumbent government and the various groups that have benefited from the current state of affairs, most of which are corporations that were able to negotiate special arrangements with the major parties in the past, so they're all kicking up a stink to try and influence public opinion.
Of course now that he's in charge of Labour and the right wing elements of the party have no way to legitimately oust him I expect they'll gradually drift from public sight or fall in behind him, though I wouldn't count on much sincerity from them in their support, and as that happens we'll settle into the normal Labour vs Cons petty bickering with each being backed by the partisan newspapers, rather than some of the pro-Labour papers trying to sabotage Corbyn.