Mr Smith goes to . . . the frying squad

Driving with cooking oil is frowned on by the police

No one fries a fine fish in South Wales better than Barrie Rees (prop: "Barrie's Plaice".) His succulent cod and chips emerge driplessly from the golden bowl of Barrie's vat. The trick is to use the finest vegetable oil, he says. In a story which invites comparison with Compton Mackenzie's Whisky Galore, some of Barrie's neighbours have discovered that this versatile condiment not only puts a glow in your belly but a tiger in your tank, too.

Mixed with a dash of meths, cooking oil apparently burns in the engines of diesel cars and trucks. And it's 40 pence a litre cheaper than the stuff you get at the pumps. One supermarket chain, Asda, has discovered that its sales of household oils have doubled locally.

In the small seaside town of Burry Port, several motorists have each been fined £500 after being pulled over by police officers inevitably known as the Frying Squad. Going by the accounts I heard from blameless drivers, the patrolmen behave like finicky buyers for foodstores rather than law-enforcement operatives. They sniff the air over a suspect exhaust pipe: if they get sunflowers, if they get olives, then the car gets towed.

As these stories suggest, the worst that can be said about the environmental impact of low-fat lubricant is that it makes your runabout smell like a chippie. A small price to pay, you might think, for what looks on the face of it like the holy grail of energy policy: a resource that really does grow on trees. Mindful of possible benefits, the government has licensed veggie fuel in a limited way. But because the Treasury never envisaged a Mazda running on Mazola, the household foodstuff doesn't attract a penny in tax. That's why HM Customs and Excise scents an evasion scam over the bouquet of extra-virgin Derv in South Wales.

It's not the first time that this community has startled the world with a transport headline. Pioneering aviator Amelia Earhart made a landing here after her Atlantic crossing. "She ran out of petrol," said Les George of the George Hotel.

"Not vegetable oil?"

"Perhaps she'd have kept going a bit longer on that," mused Les, whose saloon bar is a shrine to the flier. "It's funny, isn't it? We were the first with a woman pilot and now we're the first with this cooking oil business."

Barrie Rees doesn't let his chip fat out of his sight. He said: "If I was going to allow it to go into a car, which I wouldn't, it would have to be a Roller."

A man filling his vehicle on a forecourt in the traditional manner pointed out that this was a part of the world where people struggled to make ends meet. Cut-price fuel was attractive. Though some drivers in the principality are bringing new meaning to the expression "fast food", they're in the folkloric tradition of smugglers outrunning the duty men. Watch the wall, my darling, while the white van men go by.