In what looks rather like the thin end of the wedge for eventual privatisation of the phone company, BellSouth Corp yesterday said it had reached agreement to buy a 12.5% stake in France Telecom Mobiles Data SA, a newly formed unit of France Telecom. The new company will be involved in building and operating a mobile data network throughout France, but terms of the agreement were not disclosed. BellSouth Mobile Data Inc will provide help on the mobile data network project, which will use Mobitex technology from L M Ericsson Telefon AB. Service is due to start in Paris this year and in other metropolitan areas next and BellSouth will invest more than $80m in the network, which will cover 60% of the French population. And Mannesmann Mobilfunk GmbH has been invited to join a consortium run by Societe Francaise du Radiotelephone SA which will build a rival mobile data network; its Mannesmann Eurocom GmbH unit will have a stake of about 10%. Societe Francaise already runs one the France-wide analogue cellular telephone networks.