Guardian: The Gulf of Mexico disaster was always going to hit BP in the pocket. But as the costs of the spill keep rising, it could end up finishing off the British oil giant . Until now, the City has fretted over the fate of BP’s dividend, supposed to be $10bn, due this year. Tony Hayward, BP’s chief executive, has stuck to the line that the company is able to meet all its obligations to its shareholders and to the clean-up effort. Even last week, the question had been not whether BP …