London's population of 8.6 million is among the most diverse in the world and it is rare for identity politics to enter British campaigning.
But Goldsmith, with the support of Prime Minister David Cameron, has for weeks focused on Khan's faith and past appearances alongside radical Muslim speakers, accusing him of giving "platform, oxygen and cover" to extremists.
Last week the campaigning took a new twist as Kahn's party was accused of failing to stamp out anti-Semitism in its ranks amid a row over comments by another lawmaker on her Facebook account saying that Israel should be moved to the United States....