Oil giant BP has confirmed Tony Hayward is to step down as chief executive of the group on October 1 to be succeeded by fellow executive director Bob Dudley.Dudley currently runs the recently-established unit responsible for clean-up operations and compensation programmes in the Gulf of Mexico. He joined BP from Amoco after the merger of the two companies in 1998. He was president and chief executive officer of BP's Russian joint venture, TNK-BP, until 2008.Dudley will be based in London and his current duties in the US will be assumed by Lamar McKay, chairman and president of BP America.Hayward will be nominated as a non-executive director of TNK-BP."I believe the decision I have reached with the board to step down is consistent with the responsibility BP has shown throughout these terrible events. BP will be a changed company as a result of Macondo and it is right that it should embark on its next phase under new leadership," Hayward said.BP said that under the terms of his contract Hayward would receive a year's salary in lieu of notice, amounting to £1.045 million.In a separate statement the company said it has taken a £$32.2bn charge in respect of the Gulf of Mexico oil spill, including the $20bn it has already committed to putting in escrow.As a result the company reported a headline replacement cost pre-tax loss of $16.97bn for the second quarter, compared to a profit of $3.14bn the year before.