REAL life fuel consumption figures have exposed a massive nine miles per gallon difference between the most and least efficient 1.8 litre upper medium sector petrol engined cars. This means a potential fuel cost saving of £1,706.71 per car for a fleet switching from the most thirsty to the most frugal car in the class.

Figures from Harpur UK, which operates the Dialcard and Overdrive fuelcards, have identified a significant discrepancy in fuel consumption between otherwise competitive models. Research also exposes the weakness of relying on official Government fuel consumption figures as anything more than a vague guide to the genuine fuel economy performance of cars.

The Mazda 626 1.8 topped the chart - the figure is based largely on the outgoing 626 - with an average fuel consumption of 35.31 mpg, a full 9.06 miles per gallon better than the lowest placed Peugeot 406 1.8 LX which returned 26.25 mpg. Extrapolated over a typical 60,000 mile fleet contract, the Peugeot would require 586.5 gallons more than the Mazda to cover the same distance, which at today's price of £2.91 per gallon equates to an extra cost of 2.91 x 586.5 = £1,706.71.

The Vauxhall Vectra 1.8, for example, receives an official combined fuel consumption figure of 33.6 mpg, yet returns an average of 34.95 mpg. On the other hand the Ford Mondeo 1.8 posts an official figure of 35.3 mpg, but returns only 32.98 mpg. A fleet which opted for the Mondeo over the Vectra purely on grounds of its superior fuel economy would have to reverse its buying decision in light of the consumption achieved under real life driving conditions.