With the general election campaigns well underway, a slew of polling is coming in, - feeding the ravenous appetites of those who want to know how the vote will turn out in six weeks' time. But just a week in, there is already somewhat of a chasm between what different pollsters are saying in these voter intention surveys. On the 'narrow' side, JL Partners had Labour 12 points ahead of the Conservatives - three points closer than their last set of results from a month earlier.
And then another group, such as Opinium and JL Partners, reallocate the 'don't knows' in various ways. Prof Jennings says: 'Opinium uses how people voted at the last election and assume that they will vote the same way - this tends to favour the Conservatives, because people who voted for the party in 2019 tend to be heavily represented in this group, as there are just more of them.