Good news for fans of disruption: Uber is legal in London, following a high court ruling backing up Transport for London’s decision to allow the cab app to operate in the capital.

For those who had been following the case, the ruling came as little surprise. Uber was quietly confident in the run-up to the decision, aware that that the letter of the law was firmly on its side.

At the heart of the case is the definition of a taximeter, the device that sits in a black cab which enables fares to be based on distance travelled and journey time. The regulations that govern public transport in London are clear on one thing: a taximeter is only allowed to be installed in a black cab regulated by the Public Carriage Office. Minicabs, such as those run by Uber, are not allowed to use taximeters.

The London Taxi Driver’s Association had argued that, when Uber drivers pick up passengers, their smartphone acts as an illegal taximeter. And their argument sounds convincing – a journey with Uber varies in price depending on the distance travelled and the time it takes, and that information is gathered through the driver’s smartphone.

But the regulations are also clear that a taximeter is strictly defined as “a device for calculating fares” which is “equipped” in a private hire vehicle. In the end, Justice Ouseley agreed with what Uber had been arguing all along: a smartphone is not a device for calculating fares, and it’s not equipped anywhere. “I reach that conclusion as a matter of the ordinary meaning of the words as applied to the agreed facts,” he wrote in his judgment.

The LTDA has vowed to appeal to the supreme court on the matter, but their chances are slim. The law is what the law is, and unless they manage to convince the court that the “ordinary reading” of the words should be disregarded, it looks set to stand.

But while Uber is in accordance with legislation, it’s less clear whether what it does adheres to the spirit of the law.

The spirit of a law is not, of course, legally enforceable. That’s why laws are written in carefully considered words rather than vaguely hopeful feelings.

The law regulating taxis exists for a reason. If you're stepping into a random vehicle you need a bit of security

But the law regulating taxis exists for a reason. If you’re stepping into a random vehicle on the street, you need to have a bit of security. Either that comes in the form of pre-arranging how much you pay, as with a minicab, or it comes from knowing that whatever the fare is, it’s delivered in a strictly fair manner. Until relatively recently, that meant a taximeter in a regulated cab: only the strong hand of the Public Carriage Office could ensure drivers wouldn’t submit to the urge to mess with fares.

Following the ruling, however, the law puts us in an odd place. Pre-arrange your fare, get in a cab with a regulated taximeter, or a new option: get in a car with a smartphone app which decides your fare itself.

In effect there are now two groups of people who are trusted to regulate taxis. Familiar black taxis run by the Public Carriage Office, which pick people up from the kerb when they stick out their arm and use a taximeter to calculate the fare, then the new not-taxis, which anyone with a software development kit and a minicab license can run, utilising smartphone software (not a taximeter) to calculate the fare.

But if those software not-taximeters are fitted into a car as a purpose-built unit, they become illegal. And yet if the operators of these systems did something flagrantly anti-consumer (say, randomly adding £10 to every hundredth fare) then, provided there’s a warning somewhere buried in the terms and conditions, they would be legal.

The current situation can’t stand. Either the spirit of the taximeter legislation is appropriate for the 21st century, or it isn’t. If it is, and the legislation is merely phrased anachronistically, then parliament needs to update it so that it covers apps such as Uber, ensuring that only regulated black cabs can continue to charge based on time and distance travelled.

But if it isn’t – if the internet and smartphones enables passengers to hold drivers and minicab firms accountable in a way which they weren’t in the 20th century – then it needs to be rewritten to acknowledge that, rather than simply allowing firms like Uber to exist through a fortunate technicality in laws drafted a decade before the first iPhone was released.