Drivers, represented by GMB union, will demonstrate at City Hall against the introduction of English language requirements by Transport for London.
Hundreds of drivers are expected to turn out to protest against the "ludicrously priced" exam. All drivers of private hire vehicles are required to prove they have the required level of English in order to get a licence to drive a minicab in London.
Those who can't produce evidence of GCSE-level English must take an exam costing £180. In addition to the cost, drivers are angry at the "belittling classroom conditions".
“It’s completely unfair – everyone agrees private hire drivers should be able to speak a reasonable level of English, but forcing them to shell out almost £200 to complete an essay is far too much," said GMB's Steve Garelick.
In a rare agreement between rival groups, Uber has also challenged these rules.
It was given a judicial review by the courts and argued it unfairly discriminated against some people. However, TfL moved forward with the rule, binning exemptions for those from English-speaking countries, meaning it applies to all drivers regardless of nationality.
“It’s disappointing that, to try and dig themselves out of a legal hole, TfL is now insisting every private hire driver in London must have essay writing skills," Uber said at the time
"Thousands of drivers who’ve spent years providing a great service to Londoners will now have to fork out £200 and pass a writing exam, try to find an old GCSE certificate or lose their licence and their livelihood."
GMB has also written to the London Assembly about the matter.
Minicab drivers, including those who drive for Uber, last month staged a protest in Westminster against the firm. Members of the United Private Hire Drivers union called on the London mayor Sadiq Khan to take action over matters such as workers rights and the number of minicabs on the road.