London mayor Sadiq Khan has called for a cap on the number of robotaxis on the capital's streets, because nothing says "world-class city" like a fleet of driverless cars stuck in traffic on narrow roads while a human in a safety seat watches Netflix. The UK government is poised to allow fully driverless vehicles to operate in London, but Khan thinks politicians have failed to "grasp the pace of change" - a polite way of saying they're still trying to find the power button.

Khan questioned whether the rules for autonomous cars are fit for purpose, which is a bit like asking if a chocolate teapot is fit for purpose. His comments came after Chinese robotaxis, now being tested in London, were unveiled by Freenow by Lyft, a rival to Uber. In September, Uber started offering limited passenger services in Wayve's self-driving cars - albeit with a safety driver in the front seat, presumably there to remind the car that it's in London and should panic accordingly - under licence from Transport for London (TfL).

Freenow by Lyft is hoping to launch fully driverless Baidu robotaxis as early as next year under a national licensing scheme. The companies, as well as Waymo - which operates robotaxis in San Francisco and other US cities - are primarily focusing on London, and Khan said the city needed to be able to limit the rollout. "What we don't want is a situation where there's a big bang without proper regulation in place," Khan said, adding that regulation must be fit for purpose before any mass rollout. "I think the pace of change when it comes to tech and innovation has not been fully grasped by politicians," he added, which is the politest way anyone has ever said "you're all a bit slow on the uptake."

Khan's office is lobbying the government for TfL to have more powers over automated vehicles than it currently does. He raised "big questions that haven't been answered yet": what impact will this have on air quality, on congestion, and on those people whose livelihood is being a private hire vehicle driver or a black-taxi driver? Drivers' unions have held protests at the London HQs of Wayve and Waymo in recent weeks, with many Uber drivers fearing for their future - a future that apparently involves being replaced by a car that can't even handle roadworks without a human intervention.

Khan added: "Is there going to be a cap? At the moment there's no cap on the number of private hire vehicles or taxis. We've lobbied for those powers as well." He then delivered the line that every Londoner knows to be true: "London isn't San Francisco. We're a city of almost 10 million, 400 villages, narrow roads, and it's really important to get this right." Yes, San Francisco has hills and tech bros; London has 400 villages, narrow roads, and a deeply ingrained belief that the rules of the road are merely suggestions.

Under current regulations for fully autonomous vehicles, TfL can only give or refuse consent for their use within London and not manage or license robotaxi services, making the capital's authorities somewhat less enthusiastic than ministers to accelerate towards the new technology. Freenow by Lyft, however, said the UK's national framework for driverless cars was an important factor. Danny O'Gorman, UK and Ireland general manager, said it was "great news for us to really invest in the market. But in terms of how it's going to be regulated, once the service is up and running, that's something that still needs to be ironed out." Nothing says confidence like "we'll figure out the rules later."

O'Gorman said the company was working closely with TfL and "wanted to do things the right way." About 24 autonomous Baidu Apollo Go vehicles are being tested in the London borough of Brent. The spacious Chinese cars, which incorporate a massage seat and a built-in touchscreen in the back for passengers, are in fully autonomous service in cities in China and the UAE, and appeared to be handling the streets safely in a test drive in October for the Guardian. But many test trips still require human intervention, with roadworks proving difficult. For autonomous vehicles, "an interesting challenge in London is following the rules of the road," O'Gorman said, when many drivers ignore them: "You get beeped at a lot for following the speed limit." In other words, the robotaxi is the only entity in London actually obeying traffic laws, and it's being bullied for it.

Freenow by Lyft is promising a purpose-built AV depot in the UK, and O'Gorman said a large proportion of displaced taxi drivers could be employed there in remote operating and servicing jobs. The company has traditionally worked with black cabs, and he said: "The larger risks to that industry are the driver age profile: two-thirds are over 50 and they're retiring, and the vehicle's too expensive. AV is not going to be really competing in that space and it's going to take a long time for us to scale up to vehicle numbers that threaten anything to do with that." So rest easy, black-cab drivers: the robots are coming, but they'll be stuck behind a roadworks diversion in Brent for the foreseeable future.