YOU may have noticed there's a bit of a panic at the moment about diesel cars. You must live in a cave if you haven't.

Not that Volvo is in the eye of the storm (which hovers over Germany), but it does sell rather a lot of diesels, so has an interest in the fuel's continued widespread use.

Much of the heat generated in the diesel debate concerns the gas that comes out of the exhaust pipe but we'll concentrate today on the other aspect of life with a diesel car - the rate at which the fuel gauge descends.

All car makers have to use the same official test to measure their cars' fuel use - even if the end result is always an official fiction. It doesn't represent the real world and the sooner it does, the better.

That's still a year or two away, after the lawmakers and car builders have agreed a new test. Lots of lawyers are currently earning lots of money in the process.

But even if the present test is deeply flawed, there is no debating the fact that a diesel car will use less fuel than one with petrol in its tank. For many users, especially those with a space in the company car park, that's enough to swing the deal.

The V40 driven here uses a version of Volvo's latest diesel engine range and produced a strong 54mpg on the trip computer after more than 500 miles of varied use.

That's an impressive figure for a car that will take four adults (five at a modest pinch) a very long way in comfort. A long way from the mandated official figure, but they always are.

One way to edge closer to the brochure numbers is to take it a bit easier on the motorway, where diesels in particular shine if you keep the throttle pedal still and let the Audis and Bee-Emms hurtle past.

It's strangely gratifying to watch the distance-to-empty figure click upwards as the miles mount - with one 100 mile journey resulting in a nett gain of 50 miles worth of juice left in the tank.

Defying physics (almost) results in a door to door time stretched by a minute or two and the smug glow of a driver who has saved the planet (by a smidgen) and been easier on the pocket at the same time.

The V40 is a fine place to economise on fuel, with a cabin set out along typically sensible Volvo lines, where everything is easy to read and use and where enough buttons have been retained to show how much safer they are than stabbing fingers at symbols on a touchscreen - and cursing when you hit the wrong one.

The car was fitted with heated front seats (cosy in seconds) and a heated windscreen (useful when the frosty morning arrive) and the same £375 lux winter pack includes, of all things, an illuminated gear knob. Who says the Swedes lack a sense of humour.

More sensible options include a proper spare wheel (and jack) for £150, instead of a can of pressurised gloop, and a grocery bag holder (and flexible, multi-position load floor) for £100. Both sensible choices.