Just when foreign investors thought it was safe to paddle in Russian waters, up looms another shark fin. A $2bn investment by Norway’s Telenor is under threat in a brawl that echoes last year’s TNK-BP debacle. One of the protagonists, Mikhail Fridman’s Alfa Group, is even the same. But this fight is arguably more troubling. TNK-BP operates in the politically sensitive oil business; Telenor is in humdrum mobile telecoms. And since the Norwegian state controls Telenor, there are diplomatic implications too.

Alfa’s telecoms arm, Altimo, and Telenor own 44 and 29.9 per cent of Vimpelcom, Russia’s number two mobile operator. The two have fought bitterly since Altimo took Vimpelcom into Ukraine via a 2006 acquisition, so competing with rival Kyivstar – which Telenor controls, with Altimo as junior partner. Telenor says its objections to Vimpelcom’s move were illegally overruled; Altimo argues Telenor delayed Vimpelcom’s expansion into a fast-growing market.