Guardian: <figure> <figcaption>The site of the Deepwater Horizon oil spill in the Gulf of Mexico. Photograph: Jae C. Hong/AP</figcaption> </figure> BP came under further pressure from the City today when its credit rating was downgraded, hours after its chief executive admitted the company had not been properly prepared to fight the Deepwater Horizon oil leak. Credit ratings agency Fitch cut the rating on BP’s long-term debt by one notch to AA from AA+. It also lowered its outlook on …