Hundreds of Uber drivers and other 'gig economy' workers are to stage a protest march through London on Tuesday.
This is to be ahead of a Court of Appeal hearing linked to the employment rights and status of drivers working through the app.
The demonstration, which is part of nationwide action, has been named "rise of the precarious workers".
The Independent Workers Union of Great Britain, which is involved in the case, expects it to be the biggest ever protest of its kind in the UK.
The protesters will march to the Royal Courts of Justice, then go to the University of London before passing NHS contractor The Doctors Laboratory, where medical couriers say their pay has been cut.
Couriers, riders, outsourced cleaners, restaurant workers and others will be involved and rally will also be held in Glasgow.
Uber case co-claimant and IWGB United private hire drivers branch chairman James Farrar said: "What is clear from the different kinds of workers supporting us in this demonstration is that unity among precarious workers has never been stronger and together we will defeat the dishonest bosses that are trying to do away with our most basic employment rights."
The GMB, which is also involved in the case, said Uber drivers are on average of £18,000 out of pocket, according to estimates, two years after the company lost an employment tribunal case over the employment status of drivers.
Last year, Uber took the case to the Employment Appeals Tribunal and lost.
Sue Harris, the GMB's legal director, said: "These figures lay bare the human cost of Uber continuing to refuse to accept the ruling of the courts.
"While the company are wasting money losing appeal after appeal, their drivers are up to £18,000 out of pocket for the last two years alone."
An Uber spokesman said: "Almost all taxi and private hire drivers have been self-employed for decades, long before our app existed.
"Over the last two years we've made many changes to give drivers even more control over how they use the app, alongside more security through sickness, maternity and paternity protections.
“We'll keep listening to drivers and introduce further improvements."
They also referenced a study which stated drivers earn the London living wage and said if the drivers were classed as workers they would lose some “freedom and flexibility”.
