Did you notice the news items last week claiming new cars had become cheaper than second-hand ones? The implication was that you now had to pay more for, say, a Ford Fiesta because someone else had owned it. “The world is your lobster, my son,”Arthur Daley would no doubt have told his fellow used-car salesmen. “Fill your boots.”

The claim is not all it seems. If it were, we could earn money by buying new cars, then selling them back for more than we’d paid. It’s worth taking a moment, though, to explain how the story arose and why in future it might be possible for old cars to be worth more than newer ones. It gives an interesting perspective on the state of the car industry.

First, the facts. It is true that some used cars are priced higher than new ones. That’s because sellers of used cars haven’t kept up with the big discounts offered by manufacturers. It doesn’t mean used cars are being sold at the advertised prices.

Pick up a magazine or surf the net and you’ll find examples: www.drivethedeal.com is offering brand new Saab 9-3 convertibles for £17,995 (a saving of more than £11,000 off the list price), while a used example of the same, registered 2008, with an 08 plate and 3,000 miles on the clock, is being offered for sale by a Saab dealer at £23,450. You can get a brand new Renault Grand Scenic 2.0 VVT for £15,195 courtesy of www.carquake.co.uk, compared with £17,000 for a 2008 08 with 2,500 miles from a Renault main dealer. Astute customers won’t hesitate to buy new, taking advantage of the lengthier manufacturer’s warranties and choice of colour and trimmings.

Jason Dawe, The Sunday Times’s used-car expert, has identified another interesting trend. Because fewer people are trading in their old cars at the moment, average used-car prices have been climbing. In the past few weeks, when the average three-year-old car would normally have fallen in value by about 2% a month, it has been going up, last month by an average of 6%. Those figures reflect changes at the cheaper end of the market. Logic dictates that the real prices of nearly new cars fall in line with those of new ones.

The new-car bonanza won’t last for ever, of course. Car factories are on short time working. The owners have taken the uncomfortable steps needed to cut production, so when the surplus has been sold, the new-car deals will start to evaporate. The slippage in exchange rates means many car makers have already put UK prices up.

So are there circumstances under which newer cars could be worth less, on average, than older ones? The answer, intriguingly, is yes. You may have read about a proposal for a scheme called scappage, under which the government would provide cash incentives for customers to trade in old cars for new ones that pollute less. A subsidy of £1,500-£2,000 for a 10-year old car — on a par with the deals offered by the governments in Germany, France and Italy — is being proposed.

If Peter Mandelson, the minister in charge of trade, approves the scheme, at an estimated cost of £150m, he would become the single most influential player in Britain’s used-car business. Swiss Toni, from The Fast Show, would have had a field day. “Buying this motor is like making love to a beautiful woman,” he would croon to customers, “and the government will pay for the wine.” Maybe it isn’t such an unlikely comparison. Flashy suits, smooth sales patter, coiffed hair and a penchant for a ’tache — are Peter and Toni related? I think we should be told.

The scheme might well work — it has been credited with boosting car sales abroad — but it’s worth bearing in mind the side effects. First, it isn’t necessarily good for the environment. The energy and materials used in new cars will cancel out some of the benefits of lower emissions. Second, it could give rise to the perverse situation in which a 10-year-old car would be worth more than a seven-year-old car. I know one or two speculators who are already hanging onto old bangers in the belief they will be able to cash in.

Like all government schemes that distort the market, from wartime rationing to the common agricultural policy, there is always a way to make money on the side. As Arthur Daley might have said: a nice little earner.