Could Labour really lose London? A new poll out today shows that Sadiq Khan’s lead over Susan Hall is down to just ten points, ahead of the capital’s voters going to the polls tomorrow. The survey from Savanta for the Centre for London gives Khan 42 per cent of the vote, followed by Hall on 32 per cent and then Liberal Democrat candidate Rob Blackie in third with 10 per cent. It points to the race tightening, with Khan’s lead dropping three points since the last Savanta poll. The findings are a striking contrast with a separate YouGov poll which gives Khan a massive 22-point lead.

How best to explain this split? One leading pollster admits that their peers ‘are very nervous about London’. They question whether the samples used in some mayoral polls have enough voters who backed Shaun Bailey in the last contest in 2021. There is also a clear enthusiasm gap, with Susan Hall’s smaller pool of voters more fired up than Sadiq Khan’s larger base. Pollsters ought to therefore adjust their findings to take account of the likelihood by which people vote.

The five previous mayoral contests in London have seen turnout range from 34 to 42 per cent. A figure towards the lower end of this range is expected to favour Hall, given the strength of feeling from anti-Khan voters. The incumbent mayor enjoys a large but passive and unenthusiastic potential vote share while Hall’s potential vote is smaller but more likely to turn out. ‘If it’s less than 35 per cent, Susan wins,’ one Tory Assembly candidate says. ‘If Khan gets more than that, he does.’

The incumbent mayor is likely to be re-elected tomorrow but it will not be a landslide triumph. One pollster puts his probable margin of victory at seven points; another gives it to Khan by eight. Both agree that he is likely to significantly underperform his party. Given London Labour’s whopping lead over the Tories in Westminster polls, Khan can afford to have a bad night and still be returned for a historic third term.