The Western world has finally become determined to lower vehicle emissions despite years of looking the other way

The issue is not new, but the combination of outrage over the VW emissions scandal and advances in technology have put the issue at the top of the political and environmental agenda

Getting rid of vehicles driven by diesel and petrol engines is becoming one of the great seismic shifts of our age (Getty)

The UK’s ban on the sale of petrol and diesel cars from 2040 will be extended to include plug-in hybrids too, under a new plan called Road to Zero.

Some MPs want the ban to come forward to 2030. Paris and Rome are to ban all diesel cars from 2024. And Oxford is going to ban all non-electric vehicles from its centre by 2020, to become the world’s first city to end the reign of the internal combustion engine.

Those at least are the headlines of recent weeks, the Road to Zero one being leaked on Friday. The detail, as always, is more nuanced. This plan envisages electric cars being allowed to have petrol engines too. It is just that the electric range has to be at least 50 miles, whereas most plug-in hybrids now only have about 30 miles. But we are talking at least 10 years away and given the advances in battery technology that should be easy to achieve.

The Paris plan is to ban diesel cars by 2024 (but not, as I understand it, delivery trucks) and petrol ones by 2030, but the implementation does sound less hardline. The city’s municipal authority says: “The aim is no way formulated as a ‘ban’ by 2030, but as a trajectory which seems both credible and sustainable.”

In the case of Rome, it seems to be following Paris, but at the moment the main thing Romans have to go on is a statement by the mayor, Virginia Raggi, on her Facebook page to this effect.

As for Oxford, the banning of non-electrics is to start with at least, confined to a handful of streets at the very centre. The main obvious casualty looks like being the famous covered market, a collection of small independent shops under a communal roof dating back to 1774, at present stocked by diesel vans that unload on its northern flank. Expect some softening of the plan there.

But – and this is the important point – even allowing for some tweaking of the regulations, getting rid of vehicles driven by diesel and petrol engines is becoming one of the great seismic shifts of our age. The policy is being put in place by politicians, but this is one of those occasions where the political establishment is, if anything, lagging behind popular opinion. From an economist’s perspective the fascinating question is: why this should be happening now?

After all, concerns about the impact of emissions on health are not at all new. Back in the 1970s the US pioneered the introduction of catalytic converters, responding in particular to pressures from California. Europe eventually followed the US, but then made the catastrophic decision to encourage the switch to diesel cars. In 1990 only 3 per cent of the cars in Europe were diesel. Now it is some 40 per cent.

So what did change? I suggest two things. One was the VW emissions scandal. Once again it was the US that uncovered the trick that VW was playing, by programming its anti-pollution devices to switch on when the car was being tested and then switch off afterwards. It was a California body, founded in 1967 by the then-governor Ronald Reagan, that commissioned the study by West Virginia University that discovered this.

That sense that we, the public, were being deliberately fooled by big business stuck in the craw. The result has been a collapse of the sales of diesel cars, though as yet VW seems to have largely escaped from what might have been a financial catastrophe. It is rapidly trying to turn itself into a mass-producer of electric cars.

That leads to the second and I think more important point – technology. The internal combustion engine has dominated the world for roughly a century, utterly transforming road transport, radically cutting the cost of shipping, and making possible the development of aircraft. But it is an inelegant technology. It does the job, but it is complex to manufacture and maintain. It requires a gearbox and a clutch. It has reciprocating parts and a lot of them. It is noisy and polluting. Its fuel is volatile and dangerous to transport. A modern car engine is a masterpiece, but it has taken 140 years of development to get there.

Electric power is inherently a much “better” technology. It has far fewer moving parts and no reciprocating ones. It needs no gearbox or clutch. It has much greater torque. And above all, there is no local pollution. It has only one disadvantage. We have not been able to find a cheap way of storing electricity.

We have not entirely solved that now, but the investment needed to create batteries suitable for laptops has driven down the cost to a level where the balance of advantage has shifted. Soon it will be cheaper to make a electric car than an internal combustion one of similar spec.

I don’t need to add that the advance did not come from the established manufacturers but from a maverick inventor with no background in the motor trade – Elon Musk. What is worth adding is that the fall in the cost of making batteries is coming not from the old developed world of the US and Europe but from the soon-to-be-largest economy of all, China.

So this is a tale about politics and the environment. But more than that, it is a tale about technology. Thanks to that we can go along the Road to Zero. How we will generate electricity, though, is a whole other question.