The results put Khan a full twenty points ahead of Conservative candidate Shaun Bailey, who placed second with 23 per cent.
Sadiq Khan manages to attract 82 per cent of those who are voting Labour in the general election but also over a third of Westminster Liberal Democrat voters, whereas Bailey attracts the support of just 76 per cent of Conservative Westminster voters and almost no support from elsewhere.
Rory Stewart in third place
Rory Stewart, the former Conservative Cabinet Minister who recently announced his decision to stand as an independent, is third with 13 per cent followed by Siobhan Benita for the Liberal Democrats (eight per cent). Siân Berry for the Greens is fifth with five per cent.
Rory Stewart is drawing his support primarily from Conservatives (15 per cent of those who will vote Conservative in the general election support him) and Liberal Democrats (over a fifth of who will vote Liberal Democrat in the next general election).
Sadiq Khan remains the front-runner
The survey also asked respondents who they thought would be in the final two. The electoral system requires voters to choose a second placed candidate without being sure who will still be in the race at that stage. The top two go into a further round with second preference counted if no one wins a majority (50 per cent) in the first round. Excluding those who said Don't Know, 42 per cent of people thought that Sadiq Khan would be in the run off, followed by Rory Stewart (19 per cent) and Shaun Bailey (18 per cent).
Professor Philip Cowley from Queen Mary University of London said: "Rory Stewart has done very well to establish himself as a credible candidate in such a short space of time but the person most likely to be happy with this poll is Sadiq Khan.
"Khan's satisfaction ratings overall are positive, with more people saying they think he is doing well as Mayor than think he is doing badly. He is still comfortably ahead of the second place candidate in the Mayoral race, and the poll seems to show that he would beat any of his main rivals in the second round, regardless of who they are."
