The London mayoral elections are not due to be held until 2024 but the race to take on Sadiq Khan has already begun. Labour's Mr Khan has been in post since 2016, when he took over from Boris Johnson, and has announced he will be standing for an unprecedented third term in the capital. The election is set to take place in May 2024, along with local elections in England and Wales, and although nominations do not need to be in until two months before, parties are already putting forward candidates. Who is standing for London mayor? Labour Party Sadiq...