Cyclists often report that aggressive motorists justify their behaviour on the basis that they alone pay "road tax". But there is no such thing.
A young driver who boasted on Twitter about hitting a cyclist appears in court on Friday. Her tweet enraged cyclists - not just because of its tone, but because she claimed right of way because #bloodycyclists "don't pay road tax".
The tweet went viral and she's being charged with driving carelessly and failing to report an accident. She said in a TV interview that she regrets the tweet and didn't drive badly.
Many a cycle commuter in the UK has confronted a dangerous driver, only to be told they have no right on the road because they don't pay "road tax".
But road tax was abolished in 1937 and replaced by Vehicle Excise Duty.
This is a tax on cars, not roads, and it goes straight into the general Treasury fund. Many government agencies have now started calling VED "car tax" but it might be classified as a pollution tax, since it's now based on the size of engine and emissions. Ultra-low emissions vehicles are exempted.
But "road tax" is a powerful political idea, implying that the tax should pay for roads not hospitals, and that drivers have more right to road space than pedestrians, horse-riders and cyclists.
A trawl through Youtube shows road tax invoked as a trump card in disputes between cyclists and drivers. In one a cyclist called Themitsky is hooted by a driver whose passenger then complains he is in the middle of a lane.
Passenger: "You don't cycle in the middle of the road… You cycle on the side, not in the middle."
Themitsky: "Do you want to try it?
Passenger: "But the car have (sic) priority over you because we pay road tax."
Themitsky: "No, no"
In another confrontation recorded by helmet-camera a cyclist accuses a driver of missing him by just a few inches. He is asked in return: "Do you pay road tax?" In another a cyclist is told he has no right to be on the road: "No pay, no say".
Motorists who've been cut up by aggressive cyclists or seen them jump red lights may have some sympathy with the idea that the roads would be better if those in cars had formal priority.
The "but I pay road tax" syndrome so annoyed cycle journalist Carlton Reid that he set up a website, ipayroadtax.com. Its purpose is to persuade official bodies to lead the way in banishing this durable phrase.
"It's dangerous if motorists think that because they pay car tax they have an entitlement to the road," he says. "A small minority of drivers seem to think it gives them the right to drive badly. Language is very powerful. If we can persuade all official bodies to use the term car tax then maybe in a generation or two Mondeo Man will have stopped calling it road tax."
Road tax, founded in 1909 to fund road-building, was already on the way out by 1926 when Chancellor of the Exchequer Winston Churchill is reported to have said in a memo:
"Entertainments may be taxed; public houses may be taxed… and the yield devoted to the general revenue. But motorists are to be privileged for all time to have the tax on motors devoted to roads? This is an outrage upon… common sense."
The Treasury got its way, of course, and the tax was folded into general funds.
Reid has made considerable headway in persuading the authorities that allowing the phrase to die out like the tax itself will help persuade drivers that they derive no more benefit from what they pay to the chancellor than smokers, drinkers or any worker.
The RAC Foundation's director Stephen Glaister agrees. "Road tax implies you are being taxed to use the roads and the money goes back into the roads - that's not correct."
The DVLA - rebuked for an advert calling for people to pay their road tax - now calls it vehicle tax. The Post Office calls it car tax. So does gov.uk, the government website formed to communicate simply. So does the Campaign for Clear English. And the AA.
The chancellor calls it VED in the budget - but the Treasury now uses car tax for talking to the public.
But what about the man or woman behind the wheel? I visited the UK's original motor city Coventry to ask what drivers call the disc on the windscreen.
Out of my straw poll of 20 motorists, 15 called it road tax, four car tax, and one called it "vehicle tax monthly". Most thought it was a tax to pay for potholes.
A recent report in the trade journal Fleet Directory suggested that drivers feel that more of their taxes should be channelled into the roads.
If the straw poll is accurate, then the critics may be right - road tax may have died before WWII but its ghost will take a lot longer to expire.
You can follow Roger Harrabin on Twitter: @RHarrabin