With the majority of first choice ballots now counted, Labour's Sadiq Khan is on course to be reelected as the Mayor of London ahead of his Conservative rival Shaun Bailey.

As of 6pm, results for first preference votes in Bexley and Bromley, Brent and Harrow, Ealing and Hillingdon, Havering and Redbridge, Lambeth and Southwark, North East and West Central were all declared with other constituencies close to being completed. 

They put Khan in the lead with some 40 per cent of all first-choice votes cast.

Bailey garnered 35 per cent of Londoner's first preference votes for the capital's top job.

The Green Party's Sian Berry placed third at the time of publication, with 8 per cent.

However, with no candidate looking likely to break through the 50 per cent of votes needed for an outright win, voters' second preference choices will likely come into play to separate the top two candidates as per the London Mayoral system of 'supplementary votes'.

As such, the overall winner may not be declared until Sunday (April 9), as Londoner's second-choice votes are counted.

Tory candidate Bailey had previously opened up what was described as a "shock" lead over Khan as the first ballots were counted in several parts of the capital like Bexley and Bromley.

However, as analysts quickly pointed out, those areas were bastions of current Conservative support in London and so might reasonably be expected to return better results for Bailey.

With more and more votes being counted through Saturday, the Labour frontrunner Khan drew level with and then overtook his main rival to lead by five points in the race at the time of publication.

Meanwhile, as of 6pm on Saturday Labour were outperforming the Conservatives and other parties in the race to control the London Assembly.

Labour candidates were elected in Brent and Harrow, Lambeth and Southwark, Ealing and Hillingdon, Lewisham and Greenwich, and North East, giving the party five confirmed seats in the assembly so far.

Conservatives meanwhile won three assembly seats in Bexley and Bromley, Havering and Redbridge and West Central.