BP said that Mr Dudley has a legally valid employment contract and a work permit in place. His positions as CEO of TNK-BP and chairman of the management board of TNK-BP management remain in force.

Lamar McKay, BP executive vice president, said: I am extremely concerned that, yet again, there has been inappropriate and unauthorised interference by TNK-BP shareholder managers in this process. Representations by one group of shareholders appear to be able to override the requests of the CEO who holds the only legal authority to act for the company in these matters.

Following receipt of Mr Dudley’s work permit from the Federal Migration Service (FMS), all the correct documentation for his visa was handed to the FMS more than a week ago by TNK-BP. The FMS reportedly issued a receipt acknowledging handover of the relevant paperwork.