File photo of a worker replacing fluorescent lights on a Vodafone billboard in New Delhi

A worker replaces fluorescent lights on a Vodafone billboard in New Delhi in this June 20, 2011 file photo. Vodafone, the world’s largest mobile phone operator, missed quarterly revenue forecasts on February 9, 2012 as increasingly tough trading in Spain and Italy overshadowed solid performances in emerging markets and northern Europe. REUTERS/Parivartan Sharma/Files (INDIA – Tags: ENERGY BUSINESS TELECOMS EMPLOYMENT)