Canadian and American political watchers note that despite a poll showing most Londoners want Sir Sadiq Khan to step aside, he could still secure a fourth term.
Observers in Canada compare this sentiment to recent Toronto mayoral polls, where incumbents also face mixed support. In the United States, major city elections such as New York's are watched for similar patterns of party loyalty and voter fatigue.
Poll Shows Majority Want Khan to Step Down
Even in the traditional Labour stronghold of Inner London, 52% of voters say Sir Sadiq Khan should not stand for a fourth term.
In Outer London, where the mayor is less popular, the figure rises to 57%, according to a YouGov poll.
The vast majority of Conservative and Reform UK voters would be expected to take the view that the mayor should stand down and let a different Labour candidate contest the mayoral election in 2028. They do, by 81% and 93% respectively.
But four out of ten Labour supporters at the 2024 general election also share that view, according to the survey.
Almost a third of voters, 31%, who put Sir Sadiq Khan back in City Hall just two years ago also say he should stand aside rather than enter the next mayoral race.
Potential Labour and Tory Challengers
Other possible Labour mayoral contenders include Brent East MP Dawn Butler, former Foreign Secretary David Lammy, MP for Tottenham, and Tooting MP Rosena Allin‑Khan.
Dawn Butler is expected to seek to become Labour's London mayoral candidate if Sir Sadiq Khan does not stand for a fourth term.
More men than women in the capital believe it is time for the mayor to move on, by 58% to 54%.
Eight out of ten Londoners aged 65 and over think the mayor should make do with three terms in office.
Two‑thirds of the 50‑to‑64 age group take this view, as do 48% of Londoners aged 25 to 49, and 41% of 18‑ to 24‑year‑olds.
Overall, 56% of Londoners say Sir Sadiq Khan should stand down and let a different Labour candidate contest the mayoral election in two years' time.
If he did go for a fourth term he would almost certainly win, and possibly quite comfortably, according to other polls that asked about voting intention.
Sir James Cleverly could be the Tory London mayoral contender.
Reform picked former Tory Westminster councillor Laila Cunningham early and she is making a name for herself, partly with her criticism of Sir Sadiq Khan on law and order.
Former Home Secretary Sir James Cleverly has emerged as the early frontrunner to be the Tory contender.
Conservative Leader Kemi Badenoch is searching far and wide for the person who would be her party's strongest candidate.
The longer a politician holds office the more vulnerable they become to being voted out or deposed by their own party.
If Sir Sadiq Khan did go for a fourth term a contest against former London Assembly member Sir James Cleverly could be close, though Labour would still be the frontrunner.
Alternatively, Ms Cunningham might succeed in getting in a two‑way run‑off against Labour under the supplementary vote system used for the London mayoral election, but she may find it harder to win once second preference votes are counted.