18:30The Ideas ExchangeSir Martin Sorrell and Sunil MittalBBC World News Duration: 30 minutes Sun 13th Jan 2013, 18:30 on BBC WORLD NEWS AfricaSir Martin Sorrell, chief executive of the advertising group WPP, meets Sunil Mittal, the founder, chairman and group chief executive of Bharti Enterprises.GenresFactualMoneyFormatsDiscussion & TalkSeriesThe Ideas Exchange Source: BBC Online