I've always been dubious of manufacturers' figures for fuel consumption. While I can see they have a use as a direct comparison between cars, they do seem to be a little on the generous side. Admittedly I'm not the most feather-footed of drivers, but even in the highest gear and with cruise control switched on I can never get anywhere near the figures in the brochure and press pack.
And there are few times when this magic number has been more important for a manufacturer than at the launch of the new VW Polo BlueMotion in Hampshire last week. The ultra-streamlined hatch is being sold on its green (or should that be blue?) credentials, and with big claims of 74mpg for the basic model and 70mpg for the better specced BlueMotion 2, the press gang was keen to find out if it lived up to the hype.
Over dinner I heard claims of figures over 90mpg, which is admittedly very impressive, but I count slipstreaming a Tesco lorry down the M3 as cheating in this test. I decided it would be more apt for me to see how the car works in my hands, under normal driving conditions, as a better test of its ability to save money.
Needless to say, it failed to hit 70mpg even with relaxed driving, but to my mind achieving 62mpg with me behind the wheel is not to be sniffed at. And it got me thinking.
On Monday this week we took delivery of our new Skoda Fabia long-term test car, a 1.2 70bhp model finished in a distinctive Tonka toy yellow. Fitted with roughly the same trip computer as the Polo, I decided to be a geek and see how much work is required to meet manufacturers' figures. I'll say this, it's hard work.
A trip to Birmingham yesterday gave me the ideal opportunity; crawling traffic and long stretches of A road and motorway to cruise down. Perfect. By the time I'd got onto the M6 on the way home the Fabia was reporting 40mpg for the journey, which ticked up to 44mpg once I'd done a bit of motorway crawling. Very good, but still a little off the 47.9mpg claimed by Skoda.
In no particular rush, I decided to cheat and tucked the Fabia in behind a German lorry to see what a difference it would make. The gauge began to climb, and within ten minutes the average figure had gone up to 52mpg and showing no signs of stopping. If you're stingy enough to do it, and don't mind having to stare at the back end of a lorry for your journey, you'll save a lot of money. But honestly, would you really do that all the time? Probably not.
So despite being very impressed at the fuel saving capabilities of the two cars I've still not managed to meet the manufacturer figures in anything I've driven without cheating. But with a weekend back home in Wales fast approaching, there's still plenty of time for me to try.