No, nothing to do with the awkward guitar chord. It's diesel fuel with 7% biodiesel constituents.

In recent weeks, not only has the price of diesel at my local garage (Tesco) increased by just under 17 pence/litre, but only B7 diesel is now available from the pumps. Nothing will persuade me that B7 diesel is not so efficient as the old, full-fat stuff.

After many vicissitudes with UK cars (mainly Rovers) I bit the bullet six years ago and bought a second-hand Honda Civic (made in Swindon, but nevertheless the shouts of "Speedo" seems to have inspired the workforce to greater diligence, compared with the old BMC / British Leyland / Austin / Rover days). Under the bonnet is a 2.2 litre diesel (i-DTec). Over the years, I have been getting some remarkable economy from it. Partly because my daily commute is mainly over open roads and motorways (US = "freeways"), I usually get 65 miles per gallon (yes, you read that right; 65mpg). My work colleagues are astounded; even with similar-sized and types of engines they can rarely do better than 40 - 45 mpg.

I put this down partly to Honda using the equivalent of VW's emission-testing cheating bastard chip. If I can potter along at a steady 65 mph with as little acceleration or deceleration as possible, the needle on the dashboard which indicates the present economy will go as far as it can. It runs "off the clock" at 100 mpg. Also, my right foot developed Scrooge-like habits when driving e.g. my old Rover 420, which had a dipsomaniac affinity for fuel if driven aggressively or clumsily, with lots of heavy braking, and hard acceleration to catch up again.

Over the last three weeks, even when I have driven with all the verve and aplomb of a bollard, I have only just been able to do any better than 60 mpg. What problem? I hear you ask. Well, up to last month I could do a daily commute of 80 miles in total on a tenner. Now, with increased prices and dilution, I can only just manage £9.90 per commute. I begrudge any extra trip to the cash-point machine that this makes necessary, even if only once every several months.

I remain unconvinced that any reduction in greenhouse gas emission from a given quantity of B7 diesel is not cancelled out by the extra throttle pressure needed to extract the same amount of work from the less efficient fuel. Also, of course, I cannot but feel guilty that every rev is not destroying more rainforest and dispossessing third-world subsistence farmers of their land. See Wikipedia's rather sparse article on the subject.

OK, in a few years I will be forced to drive a government-mandated battery-powered box, which, lacking a garage and being forced to park on the pavement, I have no realistic change of charging. As an example, in the local municipal car park, there are 100 parking spaces with a mere three recharging posts. Running an extension lead through my letter box and across the pavement is not a realistic option, even if I could guarantee being able to park in front of my house.

</grumpyoldman>