What do a Porsche Boxster, a BMW 528i SE, a Jaguar XF 3.0 V6 diesel and a London Taxi TX4 Elegance Automatic have in common? That’s right: they all cost around £36,000.

If this has you spluttering into your tea, you are not alone. The TX4, lest we forget, is based on a 15-year-old design, with a sub-100bhp proprietary four-cylinder engine from VM Motori at one end, and a live rear axle at other. It has thrived not least because it is able to meet the 7.6 metre turning circle requirement for a licensed Hackney Carriage.

I’ve been surprised it’s taken so long for another manufacturer to try and steal the TX4’s virtual monopoly. Excluding private hire vehicles and illegal moonlighters, there are 22,000 licensed taxis in London alone and a car optimised for our capital would doubtless do well in other major cities around the world.

Finally it has happened. Nissan has converted its NV200 into taxi specification and expects to get final certification before the end of the year. We should not get too excited about how this vehicle might revolutionise the taxi-riding experience: in its other life the NV200 is a van and its 1.5-litre diesel engine, while likely to be smoother and quieter than the rattler found in TX4s, has even less power.

However, there are other features that will benefit passengers a little and taxi drivers a lot. Most immediately obvious are the sliding rear doors. The TX4 doesn’t even have the old suicide rear doors that could be opened by the cabbie without leaving the driving seat. The NV200 promises unparalleled access for wheelchair users and the prospect of not having to open the offside door into the flow of passing traffic for the rest of us. Those who’ve been knocked off their bicycles by someone thoughtlessly opening a car door on them will like them too. Nissan claims the NV200 will also offer “more comfort, space and convenience”.

The attraction to the driver is clearer still. Modifications to the front suspension have provided the all-important turning circle while Nissan promises it will be “competitively priced below the TX4”, suggesting a sub £30,000 ticket for the basic product, undercutting its long-established rival by at least £2000.

But Nissan’s big pitch to the taxi drivers will be the NV200’s running costs. It says the NV200’s combined fuel consumption of 53mpg compared to the TX4’s 35.3mpg will save drivers almost £700 per year in fuel alone and points out that were all London taxis NV200s rather than TX4s, that would result in 2.2 million fewer gallons of diesel being burnt. It also says that almost 38,000 fewer tonnes of CO2 would be released into the atmosphere (though somewhat disingenuously calculates this figure comparing the CO2 emissions of the thirstier automatic FX4 to the NV200 with the manual transmission that no one will buy). But it’s enough to earn the official endorsement of Boris Johnson, disability groups and the London Taxi Driver’s association.

Time will tell whether the NV200 will replace the TX4 in whole or in part, but if it does and unlike some who’ll go all misty-eyed and make comparisons to the death of the Routemaster, I won’t miss the TX4 at all. To me it always looked like a poor pastiche of a London taxi and when its TX1 parent first came out in 1997 I made the mistake of driving one and have felt sorry for London cabbies ever since. I’ve not driven an NV200 but it would be hard to see how it could be worse. So if the new cab really is cheaper, cleaner, more comfortable and quieter than the old one, I’ll be happy to see it filling the capital’s streets.