What has been causing the spike has been the tightness of the crude market. Firstly, we have had a very cold winter so far (did you see that picture of Norway's highest waterfall frozen over, all 650 feet or so of it); Russia has temperatures in Siberia down to -45C and the States has been enjoying the other side of our jet-stream ice blast - now major winter storms have been battering the east coast. This all leads to extra call on diesel and hence crude. The refiners can play some chemistry to up the diesel amount out of a barrel in winter and then make more gasoline (petrol) in summer.
On top of this the Alaskan pipeline has been down. That has taken pover 1/2 million barrels a day off the market and the States has been actively buying on the trading markets - so there's the cause of the recent spike. And the market is very sensitive to such 'incidents' when demand and supply are so tight. It is also truly a global market and if the base prices of crude and oil products are adrift geographically, then you will rapidly see trading and ship movement to profit on moving from the lower priced area to the higher one, or what is known as arbitrage in the market.