Replacing London's driver-operated buses with driverless vehicles would provide large cost savings as part of a "paradigm shift" in the way people travel, according to a controversial passage in a document published by Boris Johnson this week.

However, the loosely worded job-cutting suggestion had to be swiftly disowned by the mayor's office on Thursday, even though the document in which the futuristic idea was aired was published in support of Johnson's 2050 transport plan the day before.

Discussing trends in transport, the document supporting the plan heralded a future in which buses might glide around the capital with no drivers – there are currently 22,500 of them – a generation after conductors largely disappeared across most of London's bus routes.

It said that driverless technology of the type being developed by Google would provide "large cost savings for buses while delivering a faster more efficient service," and added that it would become possible to provide what it called "taxi like" services "at reduced costs".

A day after the document was published, the mayor's office moved to distance itself from the remarks.

A spokesman said "there are no plans for automated buses" in the capital, and that any references to "autonomous vehicles" in the report "should be seen in the context of automation on the tube". Controversy about driverless technology is nothing new in London, where there has been a long battle to introduce automation on the underground.

Boris Johnson promised in 2012 to introduce driverless trains to the underground, in a bid to reduce the power of the trade unions and end what he described as "pointless" tube strikes.

Currently only the Docklands Light Railway runs with no drivers in London, although that network still requires a member of staff on each train for safety.

The Victoria line is viewed by some transport observers as the most likely candidate for a driverless "upgrade", because it already uses an automatic system that performs all the functions of the driver, except for the opening and closing of the doors.

Under the heading "Will vehicles still need drivers?", the supporting document nevertheless continues elaborating the benefits of autonomous vehicles: "helping us reach our goal of eliminating death and injury on the roads … offering a convenient alternative to private ownership, reducing the demand for parking … [and] extending access to opportunities for the young, elderly and those with mobility difficulties."

Steve McNamara, general secretary of the Licensed Taxi Drivers Association, said that he was "dubious" that the outlined visions will come to pass. "We don't have a lot of confidence in anything that comes out of TfL, to be honest, and the fact that they're suggesting it means it's almost certainly likely not to happen.

"Who knows with technology, but some of the simplest things, they still can't do. The best example is voice recognition technology.

"If you've got it on your car … it's rubbish. If you've got it on your phone, it's probably worse. They're all crap, aren't they? None of them work, and they can't even get that right. And they expect people to get into driverless cars?"

This week, the business secretary, Vince Cable, said the government would aim to promote driverless cars in Britain, as he announced a review of the laws that make them illegal and promised to allow their testing in three cities next year.

Ministers also created a £10m fund to support the development of British technology in the area.

In early July, a transport expert with the ear of City Hall published a study calling for driverless buses in the capital. Professor David Begg's report, "A 2050 Vision for London", was commissioned by advertising firm ClearChannel, and had a foreword from Peter Hendy, TfL's commissioner.

Begg wrote that "the same technology that will bring autonomous cars will make bus operations better. When buses have the same autonomous, communicating power that cars will have, they will be able to drive safely much closer to each other, too.

"Picture a dedicated bus rapid transit lane with moving buses queued up end-to-end. In this world, cars may start to function like buses, but buses could come to work like trains. And they are a lot cheaper to deploy."

Begg also predicted the end of taxi driving as a career. "Taxi fares are expensive in London. One of the main costs is the wage/return to taxi drivers. Passengers in an AV world will be able to remotely call a driverless taxi to take them to and from their destination …

"The great promise of autonomous cars is not that we could each own one – the 21st century's version of owning your own Model T, or your own colour TV, or your own PC – but that no one would need to own one at all."