Ramachandra Guha in The Independent:
Largely forgotten now are Gandhi's closest friends in South Africa, who were an English couple named Henry and Millie Polak. Henry was a radical Jew, Millie a Christian feminist. They had fallen in love in London, whereupon Henry's family sent him away to South Africa. He met Gandhi in a vegetarian restaurant in Johannesburg, and was immediately attracted to the Indian lawyer and his cause. Gandhi, on his part, took it upon himself to have Henry reunited with Millie. When Polak's father claimed that the girl was not robust enough for marriage, Gandhi wrote that if she was indeed fragile, “in South Africa, amidst loving care, a beautiful climate and a simple life, she could gain the physical strength she evidently needed”.
The appeal was successful. Millie arrived in Johannesburg in the last week of December 1905. The next day, Henry and Millie went with Gandhi to be married by the Registrar of European Marriages. The Hindu hoped to bear witness to this union of Jew and Christian; the Registrar thought this was not permitted by law. He asked them to come back the next working day. But the next day was Sunday, and the day after that, New Year's Day. And Millie and Henry had waited long enough already. So Gandhi went across to the office of the Chief Magistrate, to whom the Registrar reported. He convinced him that nothing in the law debarred a brown man from witnessing a European marriage. The Magistrate, remembered Gandhi, merely “laughed and gave me a note to the Registrar and the marriage was duly registered”. The deed done, the couple moved into the lawyer's home on Albermarle Street, where Gandhi lived with his wife, Kasturba, and their four sons. Millie began teaching the boys English grammar and composition, while helping Kasturba in the kitchen. The two women became friends, with the newcomer's buoyant nature overcoming the matriarch's natural reserve and her lack of familiarity with the English language.
More here.