9 August 2019

Has there really been a Boris bounce?


After a Conservative leadership contest that seemed to have gone on for years, last month ended with Boris Johnson winning by a landslide, and becoming Prime Minister.

The previous day, Jo Swinson had been elected leader of the Liberal Democrats, following a contest that had run more-or-less concurrently with its Tory counterpart.

Changes of major party leaders are among the few political events that tend to have broad cut through with the public. So how much of a Boris bounce, or indeed a Jo jump, has there been? There are a few ways to analyse the impact of the new leaders.

Firstly, we can look at where national voting intention polls stand. Five pollsters have completed both at least one poll since the leader changes, and one prior to them (but after the European Elections).

Relative to each pollster’s last survey prior to the change of leaders, we see that the Conservative share of voting intention is up by between 4 and 10 points (and an average of 7), the Brexit Party is down by similar amounts, while Labour, the Lib Dems and others are at more-or-less the levels they were previously.

While there is invariably some churn beneath the surface, it’s reasonable enough to call this a straight forward swing of about 7% from Brexit Party to the Conservatives in voting intention. This has been enough to put Tories ahead of Labour in most of the latest topline numbers, and ahead of the Brexit Party among Leavers in all of them.

As would be expected, almost all of the shift has been among Leave voters, together with the demographic groups favourable to Brexit.

We also had the Brecon and Radnorshire by-election, which provided Swinson with a new MP just days after taking in office, and which Number Cruncher had polled before the leadership announcements had been made.

Given that the poll was right to the nearest whole per cent on the Lib Dems and both minor parties, and close on the combined Conservative and Brexit Party share, the Labour share, as well as a range of control variables we tested, it looks likely that the difference between the poll and the results for the Tories and Brexit Party were the Boris bounce.

That would suggest a bigger swing in Brecon and Radnorshire than nationally (about 10%), but there are reasons why this might be expected. Prime amongst them is that in a by-election situation, parties not in the running often get tactically squeezed, and so the Tories had boots on the ground actively trying to squeeze the Brexit Party’s vote, which they wouldn’t have had nationally.

That matters beyond the popular vote. Thought it would be hard to replicate to the same extent in a general election, in crucial marginal contests with Labour and the Lib Dems, it could carry the Conservatives over the line.

There is also polling on the leaders themselves. YouGov found that Boris Johnson was viewed more favourably (or less unfavourably) with the people and places you’d expect for a Brexiteer. Additionally, there is evidence of a gender gap, with the new Prime Minister somewhat underperforming among women.

On the best PM question, Johnson leads Jeremy Corbyn by about the margin that Theresa May did at the start of this year, but far behind the stratospheric margins seen early in her premiership. Ipsos MORI’s satisfaction ratings tell a similar story.

There has been less polling on Jo Swinson, but MORI found the same proportions (28%) satisfied and dissatisfied with her so far. That’s roughly the same as Vince Cable started off with, so the question is how the balance changes as people make their minds up about her.

And finally, there is polling on the key issues, and in particular on Brexit. YouGov’s tracker question found that a huge majority (76%) thought the government was handling it badly or very badly, compared with only 12% saying it had gone well. This is where it was near the start of this year.

Overall, we can say that there has been a substantial Boris bounce. That has largely consolidated the Leave vote behind the Conservatives, such that – for the time being at least – most polls put the Tories in an election-winning position if one were to be held immediately.

There hasn’t yet been a Jo jump for the Lib Dems, although that perhaps isn’t surprising given that a change of Prime Minister invariably gets far more coverage. What’s more, the Europhiles have consolidated their recent gains, and continue to poll around double their standing through most of this decade.

In the current environment, even August – usually the most sedate of political months –  could turn out to be very lively indeed.

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Matt Singh is an election and opinion polling analyst and founder of the website Number Cruncher Politics