The latest London mayoral poll puts Boris on 54%: the largest lead for any candidate this year, suggesting a 3pt swing from Ken.
The change may just be random fluctuation: with London polls still only coming about once a month it’s hard to be sure. But it would also make sense that we’re seeing an impact from the accusations about Ken’s tax dealings, which broke before the poll was conducted.
Regardless of what’s caused any swing, the combined polls this year demonstrate two key issues that are determining how the race is working out.
Converting party supporters
Given that Labour’s vote is generally much stronger than the Tories’ in London – yet Boris and Ken are roughly level – it’s not surprising that Boris is doing better among his party’s supporters.
So, one problem for the Ken campaign is that it isn’t getting support from all Labour voters. In the latest poll, Ken is 10pts behind Boris among their own parties’ supporters. While this isn’t new, the gap seems to have widened this month:
Labour’s vote across the country has increased by several points since the March poll was taken. Given the closeness of the London race, this could make a crucial difference, but the lower conversion rate of Labour voters into Ken voters could reduce the benefit to the campaign if the same reluctance applies to ‘new’ Labour voters.
Winning other voters
There’s a striking difference in where each candidate’s support comes from. Despite Ken’s relative weakness among Labour voters, a much higher proportion of his voters are also Labour supporters than Boris’ voters are Tory supporters.
In fact, less than two thirds of Boris’ support comes from Tory voters, while five in six Ken voters are also Labour supporters.
The issue is that Boris is winning support outside his party base far more successfully than Ken is, and the latest poll puts this support at its highest point so far: