Sadiq Khan remains the favourite to win the London Mayor election, according to the latest opinion polling.

With election day just three weeks away, the latest opinion poll from Opinium has put Sadiq Khan on 51 per cent of first preference votes, 22 points ahead of nearest rival Shaun Bailey.

It is one of several polls to put Sadiq Khan on more than 50 per cent which, if replicated in the actual election, would see the Labour candidate declared the winner without the need for a second round.

Every Mayor of London election since the first in 2000 has required two rounds of voting to produce a winner, taking into account voters’ second preferences.

The latest poll has put Conservative candidate Shaun Bailey in second with 29 per cent of first preference votes, while Green candidate Sian Berry and Lib Dem candidate Luisa Porritt are tied for third place on eight per cent.

UKIP’s Peter Gammons is on course for fourth place, according to the poll, with one per cent of first preference votes.

Despite small differences, recent opinion polls have largely produced similar findings, with Sadiq Khan polling between 47 and 53 per cent while Shaun Bailey is polling between 25 and 29 per cent.

The polls from Opinium, YouGov and Redfield and Wilton have found Sian Berry polling between six and 10 per cent while Luisa Porritt is polling between four and 12 per cent.

Meanwhile, a recent YouGov poll conducted on behalf of the Mile End Institute found that other candidates have begun to make some headway, with former actor Laurence Fox on four per cent and ex-banker Brian Rose on three per cent.

Though there has been little difference in the polling for candidates, a recent poll from Opinium for the Evening Standard found that crime had overtaken health and the NHS as the issue most important to voters in the upcoming election.