James Forsyth at the Spectator is a commentator with whom I frequently disagree (usually because his arguments are fallacious or based on false premises). He is asking whether a party has ever come back from "this far behind" to win an election. For the purpose of his question, I'll set to one side the fact that the swings at Ealing and Sedgefield would make the Tories the largest party nationally if repeated at a GE and that the Tories won the local elections by a landslide and answer the question as is.
I blogged previously on the parallels between Gordon Brown and ex-Canadian PM Paul Martin. Paul Martin called an election in 2006 where his liberal party were showing a 5% to 10% lead in the polls. The Conservatives won easily in the end as shown by the graphic. More narrative here, but the key feature of the Conservative campaign was their "policy a day" initiative that won round the public and the media. The Conservative leader Stephen Harper isn't and wasn't seen as charismatic, but he was certainly seen as authentic and substantial.
Authenticity is the word Tim Montgomerie at Conservative Home has been using to press home what the Tories need to convey to attract new votes. I couldn't agree more. But don't expect anything I say to carry any weight. In fact the opposite will probably happen, as witnessed by my reshuffle advice to the party to retain Willetts and Maude where they are and demote Osborne.