Arun Sarin was pacing his offices on London's Park Lane "like an expectant father" when he got the call telling him that he had triumphed in the most important deal of his career to date.

It was a "very, very happy moment" in February, admits the chief executive of Vodafone, when Canning Fok, managing director of Hutchison Whampoa, rang to say that the Hong Kong conglomerate would sell Vodafone its $11bn controlling stake in Hutchison Essar, then India's fourth largest mobile telephone operator.