State-backed Rosneft has appeared as a potential buyer of BP's 50% stake in TNK-BP - welcome news for BP shareholders

Never underestimate BP's ability to mess up negotiations in Russia, but this time the oligarchs may not give the UK oil giant the runaround.

State-backed Rosneft has appeared as a potential buyer of BP's 50% stake in TNK-BP, the troubled joint venture with the very rich men behind AAR. Confirmation of the interest is welcome news for BP shareholders. Their company may finally have some negotiating options as it searches for an exit from TNP-BP.

Until today, the only public expression of interest was AAR's declaration that it might like to buy half of BP's 50% stake.

"Good faith" negotiations have to take place under the terms of the joint venture contract but BP chief executive Bob Dudley would be daft to do that deal.

Being an equal partner with AAR has produced more than enough excitement; being a minority investor in an AAR-controlled company would cause a riot among his shareholders.

Rosneft's interest raises the more attractive prospect of a proper auction, with AAR obliged to bid for 100% ownership of TNK-BP to avoid becoming a bed-fellow with Rosneft, a prospect the oligarchs probably would not relish.

Just don't expect the outcome in this knotty tale to be straightforward. A simple sale for cash is not the only possible deal.

BP could sell its shares to Rosneft and roll over some or all of the proceeds into a new venture in Russia. Or BP could accept Rosneft shares in full or part payment. Alternatively, AAR could turn the tables and offer its stake to Rosneft. But two interested parties are usually better than one when you're the seller – that must good news for BP.

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