It would be the biggest thing to pass between India and South Africa since Mahatma Gandhi moved from one country to the other. This week it emerged that Bharti Airtel, the largest mobile-phone operator in India, is holding “exploratory” talks to buy South Africa’s MTN, the biggest operator in Africa. According to the Financial Times, Bharti has indicated it would be willing to pay about $19 billion for 51% of the company. That would make it the heftiest overseas acquisition ever made by an Indian firm, more than Tata Steel paid for Corus, a British steelmaker, and seven times the amount India invested in the whole of Africa over the ten years to 2004. The deal would unite the leading companies in the world’s two most promising mobile markets.