In real-world motoring, it's safe to assume that this is true. However, there's a strange anomaly here. In the official EU fuel economy test it's the 94bhp car which produces the better result, namely 78.5mpg versus the less powerful car's 70.6mpg. This isn't particularly significant, except that the same test rates the 94bhp car at 94g/km of CO2 emissions versus 105g/km for the 74bhp car, and the upshot is that the faster ecoFLEX is exempt from annual Vehicle Excise Duty payments while the slower one isn't.Admittedly, the difference in taxation is just £20 per year, and you would have to rabidly opposed to paying money into the Exchequer to consider that a problem. The 74bhp car is almost certain to emit less CO2 during its lifetime, regardless of what the official figures say, and if expense is a consideration you might want to bear in mind that it's around £500 cheaper to buy in the first place, a statistic which completely obliterates the tax situation.You can spend considerably less still by opting for other ecoFLEX models such as the one-litre petrol model or the 74bhp 1.3 diesel without the start/stop system fitted to the object of this test. They don't cost much to tax either, but with CO2 ratings of 117g/km and 112g/km respectively they won't seem nearly as impressive to the environmental lobby.So this is the truly "green" Corsa ecoFLEX, and it's certainly worth thinking about as long as you don't need to get anywhere in a hurry. 0-60mph times don't reveal much about a car's performance, but the fact that this one takes 13.6 seconds to perform the feat is enough to tell you - as a brief test drive will confirm - that it's no hot hatch. Taking it a long motorway run would be rather a chore, but for urban and gentle country motoring it's as quick as it needs to be.It's also adequately, but not excessively, well-designed inside. Vauxhall is starting to style the interiors of some of its larger cars (such as the Astra and Insignia) with some panache, but the Corsa still tends towards the functional, and in this respect it's closer, among its obvious mainstream rivals, to the Renault Clio than to the Ford Fiesta or Volkswagen Polo. With the exception of the controls for the headlights, foglights and instrument panel lighting - which are mounted very awkwardly, low down on the dash to the right of the steering wheel - it's generally good enough for the job.My other problem with the Corsa, in three-door form, is the downward sweep of the rear side windows, which has bedevilled the car for a decade and is really due for a change. On the other hand, there's a surprising amount of fun to be had even in this notably slow version because, unlike previous Corsas, it both rides and handles rather impressively, despite occasional hints that it was set up for smooth German roads rather than dodgy British ones.Practicality is limited only by the tailgate, which tapers inwards towards the bottom in a manner which suggests that, here as elsewhere in Vauxhall's line-up, styling was considered a higher priority than anything else. Luggage space varies between 285 with the rear seats in place, which is as near identical to the opposition as makes no difference, to 1050 litres with the seats folded, which is slightly better than the Clio and significantly better than the Fiesta and Polo. If you really want a lot of space in this class, the car to go for is the Skoda Fabia, but that's available only in five-door form.One more thing: all Corsas are getting a facelift as from February 2011, so they won't look quite like the one pictured here, but there are no mechanical changes (and the rear side windows are the same shape).