There seems to be a yearning among the British electorate for a personality change in politics. People seem rather fed up of the same old spindoctored elites controlling things in Westminster. This sounds a bit like Scottish National Party (SNP) rhetoric. (I can hear Nicola Sturgeon's voice in my head as I write.) But it is not just rhetoric.
Voting patterns show that large numbers of people in Britain do want change. Many more people are voting for charismatic anti-Westminster establishment type leaders, e.g. the SNP leader Nicola Sturgeon and Nigel Farage, the leader of UKIP. Voters do not seem to know exactly what policy changes they want, but it would seem they want leadership that inspires them - with fresh approaches and ideas. Many Britons are becoming tired and distrusting of gloss-driven politicians who grew out of the fertile soils of Westminster Village. They yearn for a different type of earthiness altogether - demonstrable passion, integrity, down-to-earth personality and conversational interaction (e.g. engagement on Twitter). The populist-leadership phenomena we are witnessing is not that much to do with being left or right (what exactly does that mean and who does it represent these days anyway?). It is not all that much to do with policy change either. It seems to be more about a change of character and a desire for fresh approaches to leadership.
The Corbyn surge is a vote against the stage-managed politics of the last 18+ years. Corbyn now has his own style of celebrity. That very British attraction to a lovable underdog can do this sort of thing (think Eddie 'The Eagle' Edwards (1988 Olympic British Skier)). In addition to Corbyn, there are a bunch of other political characters the electorate are quite taken with. In addition to the aforementioned Sturgeon and Farage, Boris Johnson, the Tory Mayor of London, has a surprisingly wide appeal, largely because of his characteristically rambunctious personality.
Personality is becoming a large part of British politics and you have to have the likability factor to successfully lead a party in 2015. Johnson can make people smile and command an audience. Corbyn has quite a different style of course, but he has captured the imagination of a new generation, because in a democracy every new generation wants and needs something to fight against if they feel life could be better.
Naturally, 'the left' like to blame the Tories for things when the Tories are in power (and often when they are not in power) - and vice versa, 'the right' often take the same approach to Labour. The newer generation of New Labour leadership candidates did not really appear all that different to the Tory front bench in terms of their entrenched establishment approach. Corbyn symbolises a significant change in personality and style from the tops of both of the recent Labour and Conservative parties. Furthermore, the media like a good story. They have gladly reported the Corbyn-mania phenomenon and helped it along with greater impetus.