I am a great fan of the Opinium weekly poll for the Observer. The firm gets its full datasets out at the same time as when the poll is published on a Saturday evening and it has a series of questions in every survey that are always asked with the result that we can compare changes over time.

Opinium also has a range of cross-heads that can really add to our understanding. One group is on CON and LAB leavers and Remainers and another has a seat split with one of those included being seats gained by CON at GE2019. Like all subsets the samples are small but you can get quite a quite reliable picture looking over three to four weeks of polling for a particular cross-tab.

Another feature that I really like is that there are leader approval ratings in every survey which makes it unique in British polling. There is also the weekly “best PM” question the results of which form the basis of the chart above. Historically the problem with the latter question is that incumbents have got a very clear advantage. It is difficult for those sampled to compare the person in Number 10 with the person who only aspires to the the job.

So although Starmer has been hammering Johnson on leadership approval five or six weeks it was only this last weekend that the LAB leader topped the best PM ratings. For an opposition leader to do that is very rare – to have moved to that position in such a short time suggests that he’s really made an impact. The chart above speaks for itself and Johnson’s only comfort is tha the next election is a long tin off.

Opinium was the most accurate pollster at GE2019 getting each of the main party shares spot on.

Mike Smithson