This has come up from other readers. One bought the latest Golf 2.0TDI that had better ECDC mpg and CO2 than his previous Mk VI Golf 2.0TDI, but in the real world gave poorer economy. The obvious reason is that the EC now fines manufacturers if their corporate average CO2 is above (a completely unrealistic) 130g/km. So to avoid the fines (and benefit their customers with lower CO2 based tax), manufacturers optimise their cars for the ECDC lab test, ignoring any effect this will have on real life economy. That's why real life economy (and consequent real life CO2) is actually getting worse. But if the CO2 limits and the tests were more realistic and more achievable in real life, then CO2 based motoring taxes would go up. Which is why we are happy for the EC's unrealistic system to remain in place, and happy to provide a realistic assessment of real life economy at www.honestjohn.co.uk/realmpg that now contains more than 42,000 submissions for more than 2,500 different makes, models and powertrains. But I agree, manufacturers need to be careful to state that the only figures they are legally allowed to publicise are the ECDC test figures and that these are probably not achievable in real life.