Robert Dudley has been running TNK-BP from outside Russia
BP's Russian joint venture, TNK-BP, has confirmed that its under-fire chief executive Robert Dudley has resigned with immediate effect.
Mr Dudley's departure, which was first announced in September, is central to an agreement aimed at solving a long-running dispute over control of TNK-BP.
The Russian billionaires that own the other half of the oil firm had accused Mr Dudley of favouring BP.
Mr Dudley left Russia in July, saying he had faced "sustained harassment".
He had been running the company from the UK since that time.
TNK-BP said chief operating officer Tim Summers will now act as interim chief executive until the company - Russia's third largest oil producer - decides on a full-time replacement at a board meeting on 11 December.
Mr Summers said it was important that the transition period went "smoothly and seamlessly".
BP has already agreed that Mr Dudley's replacement should be a Russian speaker, and Denis Morozov, the former head of Russian nickel miner Norilsk, is expected to be appointed.
Mr Dudley leaves TNK-BP after five years in the top job.
The row over Mr Dudley has increased attention over the rights of foreign investors in Russia.
Under the deal agreed in September, BP and the Russian billionaires' investment vehicle - Alfa Access-Renova - will continue to both own a 50% stake in TNK-BP.