Hybrids? So what is the point?

The point is when they become diesel hybrids rather than petrol hybrids, which is now looking a distinct possibility thanks to the fine efforts of PSA Peugeot Citroën.

Confusing. An electric motor AND a regular engine? Sounds daft and expensive.

The Toyota Prius, Lexus 400h and new Honda Civic are prime examples but those cars have petrol engines, which is not exactly logical. What is needed for a credible hybrid, with ultra-low consumption and carbon dioxide emissions, is the combination of an electric motor and a modern, powerful and fuel-efficient diesel engine. PSA is very good at making those. The problem has been to get a diesel to provide a smooth, low-vibration partnership with an electric motor.

So have the French managed to do it?

Could be. They let me play with a couple of their research cars — a Peugeot 307, left, and a Citroën C4 — on a high-security test track near Paris to demonstrate progress so far.

Although four years from production, driveability was generally good and they were pretty smooth, quick and with huge potential. They were powered by modest 90-horsepower, 1.6-litre HDi diesel engines plus electric motors, yet acceleration was just as good as a 110bhp unit and fuel savings average 28 per cent. That equates to 83 miles to the gallon, with 94mpg in town, through more use of the electric motor. And greenhouse gas CO2 emissions were a modest 90gm/km against 125 on average and only 80 gm/km in town against 145.

I’ll bet it costs a fortune.

Ah, I hear experience talking. Hybrid cars are loaded with technology; they have to lug around a high-tension battery pack, an electric motor (that is only needed during acceleration and at low speeds in town) and extra electronics, which add weight and cost, both enemies of an efficient production car. And diesel engines are costlier than petrol. The cost penalty of buying a diesel Peugeot or Citroën is about £800.

PSA’s aim is that a diesel hybrid would add at most a further £800. So that’s £1,600 more than the present 1.6-litre Peugeot 307 petrol car (taking it to at least £15,700 at today’s price). The petrol 307 averages a reasonable 38mpg while the present 1.6-litre diesel version returns an excellent 57mpg.

So it all comes down to a high annual mileage to get a good return on your investment?

That’s about it. Pretax petrol prices have risen about 50 per cent over nine months and there is now the prospect of expensive petrol for the long term. And cutting CO2 emissions is a priority.

So what do you reckon?

If the technology works, if energy prices do remain high and if the price is right, we just could be welcoming PSA’s new hybrids instead of being so suspicious of them.