Vodafone thought it was home and dry when the Indian Supreme Court ruled in January that it was not liable for a R20,000 crore (£1.3bn) tax bill. Just two months later the Indian government, which had pursued the company since 2007, proposed a set of retrospective rules in the 2012/2013 budget on March 16, effectively wrenching the safety net of the ruling from beneath the telecoms giant.