TNK-BP appeared to be imploding yesterday as the oil group's finance director said that he was resigning, blaming an increasingly bitter feud between shareholders.

The departure of James Owen has compounded the impression that TNK-BP, BP's Russian joint venture that is the third-largest producer of crude oil in the country, has been left increasingly rudderless after other management departures in recent weeks.

Mr Owen tendered his resignation in a letter on Monday to Robert Dudley, the chief executive, who fled Russia on July 24 after AAR, the consortium of four Russian billionaire co-owners that is BP's partner in TNK-BP, tried to oust him from the company.

Mr Dudley, who is fulfilling his role at an undisclosed location outside Russia, said in a statement announcing Mr Owen's departure: “Along with many others in TNK-BP, I greatly regret that we are losing Jim.”

The statement added that Mr Owen had resigned because he felt that the present battle for control of the company had left him unable to continue working independently, as his role demands. His resignation will take effect at the end of August.

Stan Polovets, the chief executive of AAR, said: “Jim Owen has made a significant contribution to the development of TNK-BP and we regret to see him go. During 2 years with the company, Jim has built a strong organisation underneath him and we expect to have a smooth transition as TNK-BP considers candidates for the CFO job.”

Mr Owen had been chief financial officer of TNK-BP since January 2006. He was a member of its senior management team and one of the five senior executives making up the core executive committee. He previously had worked in a number of countries in senior positions with Chevron, the American oil giant.

Adding to TNK-BP's problems, Mr Owen's replacement must be approved by the company's board of directors, which remains divided.

Mr Owen's resignation follows that of Jean-Luc Vermeulen, an independent board member and non-executive director, who left the group in May.

A further 148 former BP technical specialists who had been seconded to TNK-BP have also fled Russia in recent weeks after problems with their work permits.

BP, which has owned 50 per cent of TNK-BP since 2003, has been locked in a fierce battle for control of the company with AAR, which has claimed that the group is being run like a subsidiary of the British oil giant.

However, Mr Owen's departure was announced amid signs of a possible slight thawing in relations between BP and AAR. Tony Hayward, BP's chief executive, met Mikhail Fridman, one of the AAR oligarchs, last week in Prague to discuss a possible peace deal that could include changes in TNK-BP's senior management and a guarantee to end an alleged campaign of harassment against Mr Dudley and others. Some analysts have interpreted Mr Owen's departure as being linked to these talks and a sign that BP and AAR could be edging closer to a deal.

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