I am not an expert in this field, Stew may be beter/ I do however work in the industry.
BP makes most of its profits from Oil and Gas sales in the US. They also have massive interests worldwide. Add to that shipping etc and you have the bulk of their profile.
Refineries buy the crude in an open market and make the vast range of products from it. Petro is almost a byproduct of this. Recently it has been cheaper to buy fuel from the continent rahter than refine it so we have been importing it. Its all down to the refining margins.
There isnt a big profit in selling petrol at the pumps so its all down to the cost through the refinery.
We were paying £350 a tone for gas oil not too long ago but the price then jumped to around £750.
To me this is the most worrying part of fuel prices, hit the cost of transporting goods and the prices in the shops rise fast. Remember importing gas by tankers has a fuel cost issue too. Its a whole can of worms.