So, I was curious as to what the current price of gas (petrol) is in the UK.
I found this site, which seems to be updated frequently, and give some good info.
It lists the prices in Pence Per Liter (p/l).
(There are 100 pence to a British Pound Sterling)
Currently, it looks like the London area is averaging 108p (or £1, 8p) to 109p.
And 1 Liter is 0.2642 Gallons
Which means, that for 1 Gallon of Gas, it's basically £4 or $8 (US)!