Sweden’s TeliaSonera has raised the stakes in its battle for ownership of Turkcell by suing the Turkish mobile operator’s chairman, Colin J. Williams (pictured), alleging he has failed to fulfil his role as an independent board member. The legal action is the latest is a long-running dispute between TeliaSonera (and Russian partner Altimo) and Turkish conglomerate Cukurova Holding over control of the firm. In a statement, the Swedish firm says it has “for years argued that the number of independent board members in Turkcell has to increase in order for Turkcell to follow [regulatory] requirements.” But it alleges such changes have been blocked by Cukurova and Williams – and were not even able to be discussed at an AGM (“a basic and clear right under Turkish law.”) “Williams has been blocking certain vital corporate governance issues as evidence that he is not acting as an independent member and impartial chairman of the board of Turkcell,” said TeliaSonera’s Cecilia Edström. “He should therefore be removed from his duties, in order not to cause the company and its shareholders any further damage.”

TeliaSonera’s latest move comes amid reports that a court ruling over the long-running ownership dispute could be imminent. Winning the case would allow TeliaSonera and Altimo to pursue their long-term goal of merging their joint interests in Turkcell and Russian mobile operator MegaFon into a single firm, which would see them become the largest shareholder in both operators. TeliaSonera owns 37.3 percent of Turkcell, while Altimo owns an additional 4.9 percent. Turkcell is Turkey’s largest mobile operator, controlling over 50 percent of the market.