By Richard Black
BBC environment correspondent
SUVs generally produce more carbon dioxide than normal cars
Four-wheel-drive vehicles, those rugged beasts designed for the open hillside but more commonly found doing the city school run, are so polluting and dangerous that they should carry a cigarette packet-style health warning.
That is the view of UK think tank the New Economics Foundation, which outlines its arguments about the vehicles - also known as Sports Utility Vehicles (SUVs) - in the magazine New Statesman.
"They're really Satan's little run-around," NEF's policy director, Andrew Simms, told BBC News.
"They make an entirely unnecessary contribution to one of the biggest environmental problems we face - global warming - and there's a huge and unacknowledged health crisis which results from vehicle emissions."
According to the World Health Organization, vehicle emissions are responsible for tens of thousands of premature deaths in western Europe alone each year.
The agency also ascribes around 150,000 deaths globally each year to climate change.
Because SUVs are generally heavier than conventional cars, they need bigger engines, which tend to produce more carbon dioxide.
In the UK, for example, a Land Rover 4.4 V8 emits 389 grams of carbon dioxide per kilometre travelled - more than twice that of a Saab 93 1.8i. Chrysler-Jeep's Grand Cherokee produces 370g/km travelled - a PT Cruiser, from the same manufacturer, just 212.
But motoring journalist Quentin Willson said that in terms of environmental damage, SUVs were "at the bottom of the smoke chain".
"If you look at things like diesel buses, old Routemaster buses, diesel taxis, any diesel HGV, they kick out 10 times more toxins than the modern 4x4 with its anti-smog equipment and catalytic converters," he said.
Mr Simms says that environment and environmental health are just one part of the story - SUVs are also more dangerous than other forms of vehicle, he says, including to those inside.
"They sell themselves as the vehicle version of a gated community, intended to make people feel safe, when in fact they're a greater danger to pedestrians, other road users and the drivers themselves."
The World Health Organization estimates that 1.2 million people are killed in road crashes each year and as many as 50 million are injured. Projections indicate that these figures will increase by about 65% over the next 20 years, which would then make car crashes the third biggest cause of death globally.
According to a study by the US Insurance Institute for Highway Safety there are many more deaths from crashes involving SUVs than in any other vehicles.
"For all crashes between cars and pickups or cars and SUVs, people in cars are about four times more likely to die than people inside pickups or SUVs," the report concludes.
"When pickups or SUVs strike cars in the side, the risk of death for car occupants relative to the risk of the pickup or SUV occupants dying is 27 to 1."
The evidence on whether people inside the SUV are better or worse off is a bit more difficult, though the US National Highway Traffic Safety Administration has found that SUV drivers have a higher rate of death per kilometre travelled than drivers of conventional cars.
Some SUVs are prone to roll over in a crash, the administration found.
Quentin Willson said SUVs were larger in the US than in Britain.
"Their 4x4s are the size of double garages and they do eight miles to the gallon and it's completely wrong," he said.
"But over here, I don't see any empirical proof that they are either decimating pedestrians or polluting on such a massive scale."
He added: "OK, we don't like the suburban mums who drive them, but are we going to have to legislate against them because of that?"
According to NEF, one in seven cars sold in London is an SUV. In an era when global warming is said by some to be the biggest threat to the planet, NEF believes they fully warrant being labelled as hazardous.
"We're sitting here in a situation where it's become completely familiar that when we pick up a cigarette packet, we see a health warning.
"But 25 years ago we would have thought it very odd.
"We would like to see a situation where it becomes totally natural on cars."
But John Lefley, director of public relations at Volvo Car UK, said: "If this is a research organisation, I would argue it hasn't done its research very well.
"There are other vehicles that are far more polluting than most SUVs, like most cars over 10 years old."
He added: "You might as well say, from a pollution point of view, all Ferraris and Porsches should be banned."
Mr Lefley said that Volvo's XC90 4x4 had achieved the same or a better pedestrian safety score, in the Euro New Car Assessment Programme, as 45 out of 47 "supermini" class cars.
"You cannot deduce that all SUVs are, by definition, dangerous to pedestrians, because that is not the case. Some are more dangerous than others.
"This argument has been imported from America without any reference to the vehicles on sale in Europe, the range of vehicles and range of engines available."