After 16 years steering the fortunes of sports car maker Porsche, its chief executive has reached the end of the road. Wenderlin Wiedeking has resigned with “immediate effect.” While credited for turning Porsche’s fortunes round in the 1990s, he had come under fire more recently for running up a huge debt, as the company acquired around 51 percent of fellow German car giant Volkswagen.Wiedeking’s departure, along with that of Porsche’s financial director Holger Haerter, follows a board meeting which lasted all night. After the talks, the luxury car brand said the departures would open the way to investment from the Gulf state of Qatar. Earlier, Porsche had announced it would seek a boost in capital of at least five billion euros. The dramatic developments set the scene for a merger between Porsche and Volkswagen after a long drawn out boardroom battle. Volkswagen’s supervisory board is meeting today when it is expected to approve the idea of joining forces with Porsche.