Why is the Conservatives’ poll lead falling?

Uncertainty over Boris Johnson’s Covid-19 policy has created doubt among Conservative voters about backing the party again.

By Ben Walker

Boris Johnson opens his umbrella at The National Memorial Arboretum on July 28, 2021 in Stafford. (Photo By Christopher Furlong-WPA Pool/Getty Images)

Five of the last six surveys have recorded a drop in the Conservatives’ lead over Labour. In the space of a month that lead has narrowed, according to our poll tracker, from 10 percentage points to seven points, with the most recent surveys putting the lead closer to four points, which would put Keir Starmer’s party within the margin of error for victory.

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So, what’s going on? The general consensus from pollsters and academics is that the Tories’ “vaccine bounce” is all but over. With uncertainty over Boris Johnson’s handling of Covid comes uncertainty about voting for him. We saw that in October of last year during the second wave of Covid-19, and the same in the early days of May 2020 – before the Dominic Cummings scandal – over the easing of travel across England. And we are beginning to see similar signs now.

But readers should not assume that a fall in Tory support (down four points) and a rise in Labour support (up three) is a sign of genuine progress by Keir Starmer’s party. What we are witnessing is confidence among those who voted Conservative at the last election falling fast, and confidence among everyone else either rising or standing still.

Support for the Tories among past voters has tumbled

Voting intention among those who voted Conservative and Labour at the 2019 election, YouGov surveys

The latest YouGov poll, for instance, illustrates just this. The headline numbers from the poll were that the Tories’ vote share fell by six points as support among their 2019 base plummeted from 74 per cent on 16 July to 61 per cent on 21 July. But relatively few Conservative voters switched to other parties, and instead moved into the “don’t know” column.

Labour, meanwhile, has made little change among its 2019 base. The number committed to the party is at 61 per cent, a figure indistinguishable from two weeks ago when it trailed the Tories by 13 points, not four.

In essence, the latest polls show an increasingly fragile Tory base. Voters are not yet fleeing to other parties, but to the burgeoning column of “don’t knows”. It’s only mathematical, then, that Labour, the Lib Dems and Greens will pick up new support from the pool of committed voters, even if they’re not gaining new voters. Conservative decline is not the same as opposition growth.