Well done Sir Mark Moody-Stuart. Make him Prime Minister.

George Ricks, Bristol, England

I don't understand why car manufacturers find ever new ways of using up oil supplies faster and faster. It seems the sub-20mpg car is the norm these days. The sub-15mpg car seems to be the criterea for getting on to Top Gear lately. The reason nobody has developed super economical cars is because power rules, and advances in materials and engineering have been used to make cars faster rather than more economical. We need to change our attutude.

David Evans, Coleford, Gloucestershire

why are these people so anti families? If you have children you need a larger car.

HG, Swindon, Wilts

The biggest opportunity for saving petrol and developing new technologies is the US. Their petrol is about $3 a gallon vs $6 in Europe. How about this suggestion for the US Presidential contenders? Tax/refund suggestion:
1) Incrementally add a tax to fossil fuels, every month (e.g. $0.10 a gallon every month).
2) Collect the tax into a separate fund, every month (approx 10 billion gallons a month * $1.20 after 12 months =$12 billion).
3) Divide the amount by the number of Americans over 18 (approx 240 million, = $50).
4) Send everybody over 18 a monthly refund cheque to spend freely ( $50 per person a month, or $600 annualised).
This uses: price signal, free enterprise, freedom of choice. This would help increase business investment, productivity, and help create new jobs. If the price of oil fell, because of less US demand, say from $3 to $1.80 a gallon, then add another $1.20 in tax and refund an extra $50 a month per person.

Hugo van Randwyck, London, UK

How many family sized cars will achieve the 35mpg limit? Very few non-diesels. If everybody changed to a diesel car, as I did last year (I now get 40 mpg in my family size car) then the price of diesel will rocket as there isn't the refining capacity to produce more diesel. If Sir Mark, as chairman of Shell, had increased the refining capacity, instead of seeking to just increase profits, then people would have a choice, which they currently don't have.

David Leslie, Perth, Scotland

I still cant see why, in this era of high technology manufacturing and design, car makers can't seem to make significant increases in fuel economy.
Why isn't it possible to have a medium sized car (or even an SUV) that will do 100mpg or more?

Surely there is a case for making cars out of lighter materials, and researching higher efficiency in engines.
Also, bring back "simple" cars, where you have to "drive" them, rather than have a computer make the decisions for you; e.g. if you dont know when to turn on/off your wipers or lights, then you shouldn't be driving.

Contrary to this, all the politicians seem to talk about is CO2 emmissions, where they should be combining lower emissions with higher efficiency. Maybe also, road tax should be calculated by factoring in; weight, number of driven wheels, emissions and fuel economy.

Then again, the more fuel that is sold, the more tax the Government get, so it's not really in there interest to see consumption drop.

Dan Rees, Bracknell, UK