It is always heartening to have one’s prejudices vindicated. You harbour an intense dislike of something, then, joy of joys, some academic from the University of Chorlton-cum-Hardy produces a piece of research that shows your loathing actually has some justification. This is the told-you-so moment.

Example: you’ve always hated broad beans? Then someone, somewhere has probably established that eating too many broad beans causes foot-rot. And you’re driven mad by the incessant cacophony of beeps from supermarket scanners? A study by a group of scientists looking for a research grant finds that if you’re subjected to it for 12 hours on the trot, you’re more likely to contract chlamydia.

So it was when we heard a few weeks ago that many “greener” cars aren’t nearly as green as they would like us to believe. Tests showed that several cars claiming admirably low carbon dioxide emissions were in fact pumping out far more of the gas than the manufacturers said.

My heart leapt when I read this. I have absolutely nothing against low-emission cars. anything produces the better. But I amThe less CO2 suspicious of the people who drive hybrids and other vehicles that are ostentatiously “green”. A Prius is for the pious. And as we have now discovered, many hybrid cars aren’t nearly as environmentally friendly as we thought.

Which brings me to bicycles. To drive your children to school in a hybrid car is not a green thing to do – even if it impresses some of the other parents. But cycle to school with them? That really will cut your carbon footprint.

Look at a few numbers. A big, flashy hybrid car might manage 30 or perhaps 40 miles to the gallon. The smallest, most lightweight, ultra-economical diesel hatchback could, at a pinch, top 70mpg.

Now, of course cycling uses up energy. Cyclists burn calories. But with a bike, most of the effort goes into pushing along the rider. With cars, most of the energy consumed is used to propel the car itself rather than the people sitting in it. A car is a heavy thing. People are relatively light. And a bike weighs perhaps a couple of stone - little more than a big bag of shopping.

The net result? Take the calories from burning a gallon of petrol. Feed those calories to a cyclist in the form of food. That should be enough to keep him or her going for around 1,500 miles. In other words, the cyclist does 1,500 miles to the gallon. If there were a pleasant, shaded bike path running along the equator, the cyclist could circumnavigate the Earth on the equivalent of less than 17 gallons of fuel.

Thirsty work, certainly, but with a low environmental impact.

None of which is to say that people - myself included - should stop using a car. But for those 70% of car trips that are less than five miles, a bike is a sensible - and profoundly green - alternative.

Even if it means your environmental credentials aren’t on show, parked in the driveway.

Explore Features

• Porsche

• BMW

• Mercedes

• Ferrari

• Bentley

• Audi

• Maserati

• Aston Martin

• Jaguar

• VW