Uber drivers and other private hire taxi drivers could be forced to write an essay to prove they can speak English under new plans put forward by Transport for London.
Drivers of London black cabs are exempt because, a TfL spokesperson suggested, they already have to do "the knowledge", which involves memorising thousands of roads and routes.
However, TfL wants other taxi drivers to "have the right level of English, which is vital for customer safety".
Uber took TfL to court over the plans, first put forward in August, but on Friday a judge ruled in favour of TfL and said it was "entitled to require private hire drivers to demonstrate English language compliance".
TfL's plans include the need for drivers to prove a standard of written and reading English that Uber has argued is too high. Uber warned it could cost 33,000 drivers across the private hire industry their jobs, and said it will appeal the decision.
The judge found in favour with Uber on other points, however, rejecting plans to require private hire vehicle companies to have a 24/7 telephone line.
The Times reported last week that under proposals drivers would be asked to write about subjects including life on Mars, river pollution, and snowboarding. Drivers who do not have a GCSE UK qualifications will also be made to sit a two-hour reading and writing exam.
TfL welcomed the move and said it would "reflect on today’s judgment and consider how best to deliver the further improvements we want to see to passenger safety and to standards across the industry".
However, Uber's general manager, Tom Elvidge, hit out at the ruling. "This is a deeply disappointing outcome for tens of thousands of drivers who will lose their livelihoods because they cannot pass an essay writing test," he said.
"We’ve always supported spoken English skills, but writing an essay has nothing to do with communicating with passengers or getting them safely from A to B."
Announcing the court action, Uber previously claimed the proposals would be bad for business, and for drivers.