Sadiq Khan is London's first Muslim mayor

Sadiq Khan, a practicing Muslim and Labour Party politician, has been elected mayor of London. This is a major political milestone in the Western world.

Londoners voted in Khan, 45, as the first Muslim mayor of a major Western capital city. He replaces Boris Johnson and take office in a metropolis where his fellow Muslims comprise about 12% of the population.

Khan was involved in an unusually bitter campaign against Conservative candidate Zac Goldsmith, the son of a billionaire, in which race and religion have proven ugly flashpoints.

Khan is a London-born son of Pakistani immigrants, who grew up with his six brothers and sister in a three-bedroom, public housing apartment. He studied law, became a university lecturer and the chairman of a civil liberties group, and was elected to Parliament in 2005.

Khan is replacing incumbent Boris Johnson who is leading the campaign for Britain to leave the European Union at a referendum on June 23. He is clashing with Prime Minister David Cameron, who is in favor of the United Kingdom remaining.