An internet survey carried out by the UK's leading used-car chain has shown that a staggering 83 percent - that's slightly more than four of every five - of British drivers believe that car manufacturers are overstating the efficiency levels of their vehicles.
Car supermarket Motorpoint ran the survey on their website and got more than 2000 responses - which means this is something the British car-buying public feels strongly about.
Over the past few years the company has documented a preference among their customers for more economical cars. From 2010 to 2012 the average 'official' fuel-consumption of cars sold by Motorpoint dropped from 5.8 to 5.3 litres per 100km.
Which makes it even more important that manufacturers should quote real-world figures for their vehicles; motoring journalists the world over measure the fuel consumption of the cars they test - or just read it off the car's trip computer! - and the difference between their figures and those of the manufacturers can be as much as 40 percent.
Managing director David Shelton commented: “Fuel efficiency is becoming a bigger factor in the choice of people's next vehicle as fuel prices continue to soar - and our poll shows how important it is that customers get accurate fuel-consumption figures to help them decide.”
However, it is possible to download actual fuel-consumption figures from fuel-injected cars - and that's just about all of them these days - when they go in for service.
If the manufacturers could be persuaded to databank those figures they could provide accurate real-world data of the fuel consumption achieved by real drivers on real roads in a particular model, even if only after that model has been on the market for a year.
But it's unlikely they'll agree because, as anecdotal evidence suggests, those numbers would be a lot less favourable than the 'combined cycle' figures they publicise now.
All we can suggest is that you look up the 'combined cycle' figures for the car you are driving now, compare them with your actual fuel consumption and multiply the advertised figures for the car you are considering buying by the same factor to get an approximation of what you should get on the new car.