I'm always wary of manufacturers MPG figures...the old rule used to be that figure minus 5, now it's more like that figure minus 10!
And, the vehicles on sale in the UK meet stringent safety and anti polluting (read weighty) measures
My diesel Smart FourTwo does about 200 miles on a tank that costs me £40 to fill up....the Mrs' diesel B Class does significantly better....Why? I do short, high speed journeys to and from work in the Smart whilst Mrs LM works about 20 miles away and is pretty much on a dual carraigeway all the way there and back at a constant speed.
However, when I had my petrol PT Cruiser convertible I was seriously considering buying shares in BP, Shell, Texaco etc.....12mpg!!!!
But, my real point is this - the cost of fuel in the UK has risen year on year, month on month, day on day (I am serious!) and we still get shafted by the Government on fuel costs....import duties, various taxes, VAT at point of sale etc because the previous Governments did not invest in home supplied / processed oil / petrol...these all add up to me swearing at the fuel pump - thank the Lord for "pay at pump" ability!!!
I do not mean to sound anti Government, it just riles me!!!!!