The Telegraph is due to publish a story tomorrow questioning YouGov's reliability and claiming that the polling group's methods have a pro-Labour bias.
Before we go any further, it's worth recalling that before signing a deal with News International this year, YouGov carried out regular surveys for . . . the Daily Telegraph.
Kellner's piece deserves to be read in full, but here are some highlights.
Asked by Winnett to explain the disparity between YouGov's figures and those of other polling firms, Kellner replies:
Comparing the average of our March results with those of our established rivals (ICM, Ipsos-MORI, ComRes, TNS), I calculate that the figures are:
* YouGov: Con 37%, Lab 32%, Lib Dem 18%
* Other companies: Con 38%, Lab 31%, Lib Dem 20%
The remarkable thing, given the variety of methods employed, is how close we are, not how far apart.
Elsewhere, Kellner responds to claims that the Sun rejected a YouGov poll showing a 1 per cent Tory lead.
Untrue. Our daily voting intention polls started appearing in the Sun on February 18. To test our systems, we started asking about voting intention, never intended for publication, for some weeks preceding that. Our poll showing a one-point Conservative lead was one of these. (It was conducted immediately after Piers Morgan's interview with Gordon Brown which, I believe, caused a real but short-lived movement in voting intention.) But this finding was never destined for the Sun and therefore never rejected by it. The Sun has published every voting intention result we have supplied.
It's fascinating to learn that the poll in question (never intended for publication) did show a 1 per cent lead and that Kellner attributed this to Brown's interview with Morgan.
Let's wait to see if the Telegraph story contains anything new tomorrow but for now it looks likes Winnett's claims don't stand up.