Meanwhile, I'm bound to say, I am losing all respect for YouGov. One of the things I have learned definitively from the current British General Election (came across hints of it in the US Presidential Election of 2010, and the previous British General Election in 2010), is that polling is really horribly subjective and biased. It is all based upon protocols for sampling and weighting.
And from what I can see, YouGov, by their own admission, changed their protocols in about March of this year, since which time they have almost consistently shown a Labour lead, against the evidence of other polls (which have at least fluctuated between the two main parties), and in conflict with their own in-depth, background analysis. Such as the tracking of peoples' views on the handling of the economy by the Tories.
I truly get that, with the experience of recent electoral results, on both sides of the Atlantic, being out of sync with polling, pollsters (who make their living from commercial polling, not political polling) want to be sure that they get their predictions right. But just how much biased guesswork are you allowed to incorporate into an activity which is supposed to be at least based on some sort of science?