Manufacturers would argue that quoted MPG figures are simply a guideline that none of us should expect to achieve.

So much so, that the chief executive of the SMMT Paul Everitt said they were “an average, of an average of the worst possible average”.

Nevertheless, we all would expect or at least hope to get somewhere near the quoted figures that manufacturers tempt us with in their marketing campaigns.

Last month, I took the A5 Sportback 2.0 TDI S Line on a 600-mile round trip to Scotland where I was left disappointed in achieving only 47.6mpg, compared to a claimed combined of 61.4mpg – a 22% shortfall.

This month, 85% of my driving has been in an urban environment where Audi claim that the A5 Sportback 2.0 TDI S Line should be achieving 51.4mpg.

It’s at this point where it’s important to stress how I drive that vehicle has a huge impact on how the engine performs in terms of fuel economy.

A heavy foot will cost you dear at the pumps and drive down what might be realistically achievable, which is why thousands of fleets employ the services of eco-driving schools to help mitigate the impact of the driver.

However, even when reading the road ahead and trying to avoid harsh braking or accelerating I have been left disappointed.

The A5 only achieved 37.6mpg against the 51.4mpg quoted by the manufacturer – a shortfall of more than 26%.

Determined to understand how I might mitigate my effect on the figures even more, I switched the in car display to show what MPG I was achieving on a second-by-second basis.

I wish I hadn’t as I quickly became obsessed and, while I celebrated those moments when I was achieving more than the quoted figure, the majority of the time was looking at figures akin to a 1970s gas guzzler.

I doubt the A5 is much different from some of its rivals in failing to deliver on fuel economy figures and I’m in no doubt my driving has a significant effect.

However, I don’t think I’m much different from the average fleet driver, so how many of us would consider a car that had a claimed combined of 47.6mpg and an urban fuel consumption figure of 37.6mpg?

By Gareth Roberts