Toyota GB has responded to assertions by UK-based motoring journalist and car reviewer Neil Winton that the Toyota Prius falls short of the manufacturer's claims on fuel consumption.

In his review of the hybrid Prius published late last year, Winton said that while he was impressed with the engineering achievement inherent in the latest Prius, he reserved the right to downgrade his rating of the car if the fuel efficiency figures turned out to be exaggerated, on the basis of an extended road test.

Winton said on his website: "The new Prius claims even better fuel economy [than the previous generation Prius]-65.7 mpg/3.6 litres-but manages to fall short by an even bigger margin. I managed 40.6 mpg/5.8 litres over about 350 miles, that's 38% short of the claim. A recent test by Britain's Autocar magazine achieved an average 41.7 mpg. I wasn't driving the car hard, and most of the route was rolling through the Sussex countryside at between 50 and 60 mph with some motorways and a little bit of town action."

Winton duly marked the car down to three stars out of five, from the previous five-star rating.

The reply to Winton's assertions from Scott Brownlee at Toyota GB, states that the official fuel consumption figures for Prius, and all other new cars on sale in the UK, are reached by following an EC Directive which prescribes exactly the test cycle to be used.

Scott suggests that Winton's results' apparent discrepancy with official figures could be down to the difference in driving style and route.

The letter goes on:

"By your own standards you may not have been driving the new Prius hard, but maintaining 50-60 mph through the rolling Sussex countryside, as you said you did, is far removed from the stop-start and low top speed the Urban Cycle test demands - a regime the Prius is well able to exploit with its low speed, no petrol engine needed characteristics. Had you tried the Prius across London I suspect you would have found a very different result, one far superior to any conventionally powered car and probably even better than the official figures allow us to claim. The slower you go in Prius the more fuel you save - something even Honda's IMA cannot match as it cannot run on electric power alone.

"Finally, contrary to the assurance you gave your readers, I can assure you and them that Toyota do avoid misleading potential buyers by pointing out that the Prius, while happy to cruise endlessly up the motorway, will not give its remarkable frugality in such use. Part of the training for salesmen on the car has always been an emphasis on qualifying the customer to make sure they do not buy the Prius with false expectations. We have no need or desire to sell the customer the wrong car for their needs, not least as Toyota has the widest range available on the UK market and can usually find another model - e.g. Avensis D-4D diesel - to better meet their needs if long distance cruising is the dominant factor."