Tony Hayward's departure as BP chief executive comes little more than three years after his mentor and predecessor also left the corporate giant in traumatic circumstances.

Mr Hayward, a 53-year-old BP lifer, took over in May 2007 from former boss Lord Browne, who fell on his sword when it emerged he had lied to a court over his relationship with another man to protect his privacy.

Lord Browne's exit dealt a further blow to an oil giant still reeling from the fatal Texas City refinery blast in 2005, which put the firm's safety record under a harsh spotlight.

The reign of the Sun King was ended after 12 years in charge, but Mr Hayward was ready to step in after being groomed as a potential successor early in his BP career, which began in 1982.

In the top job, the less demonstrative Mr Hayward was a world away from the cigars and Montrachet wine of Lord Browne - with a back-to-basics approach concentrating on "closing the performance gap" with rivals such as Royal Dutch Shell.

And under its new boss, BP stole a march on its rival - stripping out layers of management and costs across a stumbling and bloated business, improving its refining efficiency and putting the firm on a stronger footing to weather a global downturn.

All this changed on April 20, when an explosion on the Deepwater Horizon rig in the Gulf of Mexico led to the region's worst ever ecological disaster.

His understated style and discomfort with the media - as well as a series of gaffes - led to him being vilified in the US. "Hated" and "clueless" was one tabloid's verdict.

Mr Hayward, a married family man with two children, complained at the height of the crisis that he "wanted his life back" and also attempted to downplay the impact of the crisis by suggesting that the Gulf was "a big ocean", predicting a "very, very modest" environmental impact.

This put him firmly in the sights of a series of politicians seeking an easy target ahead of looming mid-term elections.