I spent yesterday morning marvelling once again at the German love for the uniquely British vehicle. A group of Volkswagen designers (as well as the German ambassador to London) gathered in a small art gallery near Trafalgar Square to present VW’s concept cab to the world.

Even now, I am still astonished at the ability of even younger Germans to become misty-eyed over bizarre old Brit vehicles, such as the current London Black cab. To me, the Black cab is crude, overweight and over the hill. To the average VW designer it’s an inspiration, in form and function if not engineering.

I was greatly amused to hear that the design team had managed to borrow a Black cab from a local taxi company in Wolfsburg and spent a couple of days pouring over it and even driving it on the local roads.

Of course, while the VW designers love the design cues and individuality of the Black cab, the engineering concept of the VW cab is rigorously logical and forward-looking.

It’s pretty heavy (1500kg against the Black Cab’s 1800kg) but then it’s fitted with a massive battery, in order to have the range for a long day’s shift. The use of touch screens to allow translation and payment are also no-brainer essentials for the cabs of the future.

Interior design chief Tomasz Bachorski told me that he couldn’t believe that today’s London cabs didn’t have clear roof panels, to allow tourists to enjoy the capital’s landscape. Sitting in the VW concept, with its extensively glazed roof, it’s clear that he’s absolutely right.

By a remarkable coincidence, on the day that the VW electric cab was revealed, London Mayor Boris Johnson unveiled his final ‘air quality strategy’ paper.

It called for ‘affordable electric Black cabs to be ready by 2020’. Johnson’s on a sticky wicket with the capital’s taxis, because the ageing 22,000-strong fleet is responsible for a disproportionate amount of the illegal levels of air-pollution in the capital. But it’s a brave politician who takes on the cabbie community.

Although Johnson is moving to push the dirtiest cabs off the roads by 2012, the impact on air quality will be minimal. But London is in a bind.

I’ve heard that Mercedes has offered to immediately offer EU6 clean-diesel versions - and eventually electric range-extender versions - of the Viano London cab.

But the vehicles will be even more expensive than today’s £35k Black cab and Cabbies are said to be extremely wary of new technology, much preferring the bog-basic mechanicals and repairability of today’s model.

There is a way to fix the problem of the belching London cab, though. Keep the current model and replace the diesel engine with a turbo petrol engine powered by gas, which could be stored in a tank in the rarely-used boot.

Cabbies keep their robust old charge and Londoners get the benefits of clean-burning gas-powered engines. The only infrastructure changes needed will be the installation of gas tanks at filling stations. But if the government pledges to keep the tax on gas low for five years, and encourage its use in all commercial vehicles, that shouldn’t be a problem.

Self-employed cabbies will not be risking their livelihoods on expensive battery-powered supercabs anytime soon. Let’s cut expensive clean-diesel and even more expensive batteries out of the question altogether and make a dash for gas.