May 2017 has seen a slight drop in average fuel prices, mirroring a similar drop in the price of a barrel of oil, which is now bang on $50.
The most expensive place to buy fuel is the South East of England, whereas if you were willing to drive to the North East you'd find the cheapest prices at the pumps (although the minimal 1.5p per litre difference would quickly negate any benefits!).
Supermarkets were on average 3p per litre cheaper than main supplier forecourts.
Sources: AA Monthly Fuel Price Report (UK Petrol Prices), US Energy Information Administration ($ Oil Prices).