Current average fuel costs for unleaded in London area = 96.9p (pence) per liter
So taking 3.785411784 Liters to get 1 gallon = 3.785411784 * 96.9 = 366.8064018696p Then converting the p to GBP = 3.66 then converting 3.66GBP to US Dollar = 7.46917 USD