Mike Rutherford: Lies, damned lies, and statistics on fuel costs

'Car-makers are building vehicles that are massively more fuel-efficient than their predecessors'

Concerned about the rocketing price of fuel and the amount of C02 your car is belching out? You darn well should be. Both need to be cut. And they can be - instantly, easily, cost-effectively and satisfyingly.

The fact is that while pump prices have risen by almost 100 per cent in 10 years, there's no reason why your spending on fuel has to rise in a similar vein. If you spent £10 a week/£520 a year on the stuff a decade ago, you can in 2005. And you will not have to reduce your distances and speeds.

Here's how. Although it probably didn't seem like it, your car in the mid-1990s may well have been a heavy, big (but not necessarily spacious) four- or five-seater, capable of 40mpg at most. Achieving 60mpg in those days wasn't just unthinkable; it was daft even to dream of such astonishing money- and planet-saving fuel efficiency.

Yet today, a lighter, smaller state-of-the-art car with similar power and four-person space will do up to 83mpg. Yes, it's depressing that you have to pay nearly twice as much for fuel now, but who cares when a gallon can take you twice as far?

If you're determined to continue paying not much more than a tenner a week for fuel by cleverly enjoying double the mpg you used to put up with in the "good old days", you must do three things: downsize to a smaller car; promise that you'll never buy another drop of horribly inefficient unleaded petrol; and find £8,000 - the sort of wedge you'll need for a cutting-edge car powered by diesel.

The £8,455 (before discount) Citroën C1 HDi is the most miserly motor on sale in Britain today. Officially (the Government, not Citroën) this model can return 83.1mpg. Surprisingly, the Honda Civic IMA petrol/ electric hybrid, costing almost twice as much, only achieves a best of 65.7mpg. The even more impressive and expensive Toyota Prius hybrid can't touch the C1 diesel either; it will do a maximum of 67.3mpg.

It's amusing, if naughty, to compare these hi-tech marvels and the modest C1 HDi, but it's more relevant to do like-for-like comparisons of small Citroëns present and past. A decade ago, a Saxo 1.1 petrol achieved an official maximum of 52.3mpg. Doing 10,000 miles a year, it needed 868 litres (191 gallons) of fuel at about 57p per litre. Total fuel expenditure was £495 a year, or £9.52 a week.

Today, the just-launched Citroën C1 1.4 HDi achieves a maximum of 83.1mpg, 10,000 miles a year needs 547 litres (120 gallons) at about 94p per litre. Total fuel expenditure is £514 a year, or £9.88 a week.

Not convinced because you suspect that the maximum mpg figures supplied by the Government are unachievable? Fine. Let's compare the more realistic combined town/motorway figures for the same two cars. The Saxo did an average 42mpg on this measurement, and needed £613 of fuel a year, or £11.78 a week. The C1 1.4 HDi does an average 68.9mpg, swallowing £620 of diesel a year, or £11.92 a week.

The fact is that whatever comparisons are made, it's clear that the weekly diesel bill for a 10,000-mile-a-year C1 1.4 today is actually only a few pennies more than for the Saxo 1.1 of 10 years ago. But in real terms, the C1 costs several pounds a week less to run.

Car makers in general and Citroën in particular are proving that they have the will and talent to design, build and sell mass-produced vehicles that are not just more fuel-efficient, but massively more efficient, than the models they succeed. That's great news.

Are makers of aeroplanes, ships, trains and buses, and central heating, cooking and lighting equipment, achieving such colossal energy-saving reductions? In a word, no. Now that can't be good news. And it's even worse news for the planet.

After all, factories, homes and public transport vehicles are much bigger, more damaging polluters than the humble personal mobility machine known as the modern motor car. Aren't they?

motoring@independent.co.uk