The UK petrol/diesel fleet gets almost twice the fleetwide MPG as the corresponding US fleet, and they drive on average only a third of the annual miles compared with those in the US. UK public transit is far superior than that available in the US. The longest straight-line road-trip in the UI is from Land's End to John 'o Groats, 603 miles (814 by vehicle).
Comparing UK prices to US prices for fuel isn't particularly useful.