When executives of Ranbaxy Laboratories and Daiichi Sankyo met in Tokyo at the beginning of the year, it was – in the words of one Indian executive – a moment in the pharmaceuticals industry when McDonald’s met a Michelin-starred restaurant.

About a year after Daiichi Sankyo, the Japanese drugmaker, agreed to buy a 64 per cent stake in the Indian generics producer, Malvinder Singh, Ranbaxy’s chairman and chief executive, has unexpectedly left the kitchen.