Alexei Sayle: Skullduggery at the pump and a cow in the car

A friend of mine had an agency job for a while in which he was paid to move cars around a giant decommissioned US airfield in Oxfordshire. The cars he drove were either brand new and waiting to go out to dealers or were almost-new fleet cars about to be resold at auction; either way, they were clean and unmarked.

But one day my friend noticed a zone in a distant corner of the airport where there were parked a large number of expensive new cars that weren't pristine but, instead, were dented and bashed up with dinged wheels, gouged and scratched bodywork and seat fabric that was disfigured with disgustingly smelly but unidentifiable stains.

"What are those cars over there?", my friend asked his boss.

"Oh those," he said, "those are cars that have come back from motoring journalists! Most of them will have to be scrapped!"

Apparently, my friend was told, a car has better chance of surviving a head-on crash at 50mph than a week on loan to a British tabloid or TV show. In their time the people at the airfield have received a vehicle back from journalists where there have been clear signs that somebody has been trying to get a cow into the back seat and a four-wheel drive returned from a television programme where someone had been running a Turkish bakery from the boot.

Apart from the moral minefield of whether its right to behave in such a way with somebody else's stuff, I wonder if acting in such a cavalier fashion doesn't affect the journalist's impartiality, in that they feel compelled to be nice about the car they've damaged. I know that if I've ever left a smelly stain on someone's furniture or they've caught me trying to sneak a cow on to their premises, I feel obliged to be nice to them for weeks afterwards.

This information will be welcome news to Citroën UK which has recently lent me a new C6 on long-term test. However, there is one aspect of the switch from petrol to diesel that is beginning to disturb me. In the three weeks since I've taken ownership of the Citroën C6, people are still stopping me in the street and telling me how beautiful it is and are even taking photographs of it, but I'm not entirely happy.

The reason is nothing directly to do with the car, but rather with the price of diesel fuel to put in it. In fact it's not even the price but rather the difference between the price of diesel and the price of unleaded. I've seen anything from 2p to 8p difference in the cost of a litre: how can this be? The tax differential is the same so what's going on?

Generally, where the differential is lowest is where the diesel is likewise cheapest, but not always. For example, I've seen unleaded at petrol stations for 88.9p and diesel at 92.9p, but then in others I've seen unleaded at 82.9p and diesel at 90.9p - so the differential is greater but the actual price is lower. Do I shop there for the cheap fuel while ignoring the owner's price manipulation? It's another moral minefield worthy of Sartre himself!

Except that of course he only ever rode a horse.

motoring@independent.co.uk