The largely unworkable joint ownership of South Africa’s largest mobile operator, Vodacom, will likely be broken. 

Telkom, South Africa’s largest fixed-line operator, has agreed to sell 15 percent of its stake in Vodacom to Vodafone, which will give the U.K. operator the controlling interest in Vodacom.

Vodafone has agreed to pay approximately $2.5 billion for the additional 15 percent stake. Telkom will distribute the other 35 percent ownership of the mobile operator to its shareholders, which include the South African government, whose ownership interest is 39 percent of Telkom.

Vodafone, the largest mobile carrier in the world based on revenue, has been stymied by subscriber saturation in Europe, its primary market. The company has sought to extend its investment in thedeveloping world where penetration is low and growth is much higher.

The deal will not be viewed as cheap, Martin Mabbutt, ananalyst with London-based Nomura wrote in a note on Friday, but in sharing control with Telkom, Vodafone was hampered in many ways in the operation of Vodacom.

“Vodafone is only having to pay this high price on 15 percent of the company, not on 100 percent, and this does give it a controlling stake,” he wrote. “However, given the current mood of the market, we doubt the deal is going to receive rapturous applause.”

On the other side, there may be little applause in South Africa.  That's because it has now agreed to relinquish control of a critical resource to a foreign company. But the generous Vodafone offer was difficult to rejecta, ccording to a South African analyst.

Vodacom provides mobile services to more than 30 million customers in South Africa, Mozambique, the Democratic Republic of the Congo,Tanzania, and Lesotho.

The deal is subject to a number of conditions including the successful negotiation and agreement of final transaction documents.

Back in June, Vodafone offered to buy a 12.5 percent stake in Vodacom for a reported $2.5 billion.

Vodafone may not seek to acquire much more than 65 percent of the company because it will begin to bump up against local black empowerment laws, which may force Vodafone to sell part of the company to black investors.