BP chief executive Lord Browne was last night thought to be on the brink of confirming plans to stand down in 2008.
He is likely to use today's second quarter earnings presentation to stress that he will leave BP when he reaches the company's compulsory retirement age of 60.
Lord Browne is considered one of the UK's most successful chief executives, having turned BP from a failing oil company into Europe's most successful large energy group. He became a BP executive director in 1991 and took the helm four years later before overseeing a push into the United States, including through a merger with Amoco in 1998.
Interest in his retirement surfaced last week when Merrill Lynch oil analyst Mark Iannotti asked whether the boardroom departure represented "a medium-term risk" for shareholders. He also considered the possibility of Lord Browne staying in the post beyond 2008.
Lord Browne is thought to have made the decision to clarify his position after discussing the move with BP chairman Peter Sutherland on Friday.
A source said: "John and the board have agreed on his retirement and the succession, and that has him going at 60."
One report said Tony Hayward, head of exploration and production, was the most likely successor to Lord Browne because BP's most important challenge was to grow the company's reserves.
Other hopefuls identified include Iain Conn, head of safety and environment, John Manzoni, who is head of refining and marketing, and Robert Dudley, who is chief executive of Russian joint venture TNK-BP.
It is unlikely that Lord Browne will step up to become BP chairman, as this goes against corporate guidelines.
Today's quarterly results are likely to see BP report profits of between $5.8 billion (£3.14 billion) and $6.3 billion (£3.4 billion).
High oil prices will have inflated the figure, despite concern over production targets following last year's hurricane season.