For years, the London licensed cab driver's badge was worn with pride. Up to five gruelling years spent scootering around the capital learning "the knowledge", plus a full medical, meant the black hackney was driven by the cream of drivers. But now there is insurgency on the block. The digital revolution that has changed so many industries is sweeping the taxi business, possibly putting the very future of the famous vehicle so loved by tourists and Londoners alike under threat.

Next month, London's black-taxi drivers are planning a mass protest in the capital against Californian technology company Uber, which is leading the changes in the way people hail cabs. Uber – like several other entrants to the lucrative cab business – allows people to use an application on their phones to see where the closest car is to them and then book it after agreeing a set fare, which is paid by credit card. No cash changes hands, and Uber even discourages passengers from tipping their drivers.

The encroachment of smartphone technology on the capital's taxi operations is being looked at by the licensing authority, Transport for London. In a statement, it said: "We've seen no evidence to suggest that Uber London Ltd are not fit and proper to hold a London private hire operators' licence, but no final decisions have been made while Uber's operating model is still under investigation."

Taxis and minicabs are regulated differently in London. Black cabs, allowed to use bus lanes and to pick up passengers who hail them in the street, are more tightly regulated and their fares are metered. Minicab drivers work under a lighter touch and have fewer privileges, but still must be licensed and registered.

Uber app.

The new cabs being "facilitated" by Uber – which says it is not a cab firm but an enabling "platform" – are, according to the Licensed Taxi Drivers' Association, being allowed to straddle both while only meeting the licensing criteria for minicabs: they are classified as a minicab service but can use a charging system more like metering, even though there isn't a meter inside the car.

London cabbies aren't alone in their protest against technology that undermines their business with just a phone and a satnav. Uber has run into opposition in 15 of the 100 cities worldwide in which it operates – in the UK that includes Manchester. There have been protests and even court cases against it in Brussels, Toronto, Paris, Berlin and New York, plus several other US cities.

Jo Bertram, general manager of Uber in the UK and Ireland, said the service was so popular that the average wait for a cab was around five minutes. "Seven during the tube strike," she added.

She was more coy on how many cars and drivers were registered to its "platform". "Our clients are giving us very encouraging feedback and we're seeing fantastic growth," Bertram said. "The private hire industry hasn't been shaken up in a decade or more. The laws governing it were written in 1988, before smartphones were even invented. All our drivers are independent operators, but clients can rate their driver at the end of a journey, so we make sure the right people are out there and the right price is charged at the end of each journey. "

The idea is very simple – if you want a taxi, you look at the app on your phone, see where the nearest car is and order it. You can then watch the little icon on screen as it approaches. The payment is taken from the registered credit card.

Nicko Williamson runs Bounce, another app-driven taxi firm. "We don't want to put the black cabs out of business. It's an iconic thing. You can hail them, and that's really important for Londoners. Will drivers stop aspiring to be a black cabbie? I don't think that's going to happen any time yet. There's still a demand, but we work on a commission model with our drivers – straight 20%. They can log on and off when they want, and we find loads of people want to be drivers. We have a fixed upfront price and our overheads are lower, without the minicab office and telephone operators.

"A lot of people don't realise how big this market is. There are 65,000 mini cabs in London. But it has been very inefficient. A driver who picks someone up in central London and drops them off out in the sticks is driving back empty. That's wasted mileage, higher pollution, higher congestion and no money earned. The app system allows that cab to be booked immediately by someone in the area."

Passengers can also be sent a photograph of the driver and the car's registration number. The whole journey is recorded on an emailed receipt. But while people can request a fare quote, the journey cost is calculated, says the LTDA, by a metering system even if the meter is not actually inside the car.

London cabbies are plotting their survival. The June protest will attract enough drivers to cause serious congestion in central London, said the LTDA's general secretary, Steve McNamara. "We're not asking for Uber to be banned. If everyone else has to follow the rules, why shouldn't they?"