Union leaders in the U.K. have urged the British public to boycott Uber, as its drivers strike across the country on Tuesday.

Drivers in London, Birmingham and Nottingham will strike from 1:00 p.m. London time in protest over working conditions and pay.

Alongside the 24-hour strike, called by the United Private Hire Drivers (UPHD) branch of the Independent Workers Union of Great Britain (IWGB), demonstrations will be held outside Uber's offices in each city.

Drivers are demanding that their fares, which currently stand at £1.25 ($1.63) per mile in London, are increased to £2 per mile, as well as a 10 percent reduction in commissions paid to Uber. UberX drivers, who provide the app's most popular service, currently pay Uber 25 percent commission on their earnings.

In 2016, a British employment tribunal ruled that Uber could no longer treat its drivers as self-employed contractors, which the company has continued to appeal against. Another demand of those on strike is that Uber complies with the ruling by granting its drivers workers' rights, such as the minimum wage and paid holidays.

An Uber spokesperson told CNBC via email: "We are always looking to make improvements to ensure drivers have the best possible experience and can make the most of their time driving on the app. That's why over the last few months we've introduced dozens of new features, including sickness, injury, maternity and paternity protections."

"An academic study last month found that drivers in London make an average of £11 an hour, after accounting for all of their costs and Uber's service fee. We continue to look at ways to help drivers increase their earnings and our door is always open if anyone wants to speak to us about any issues they're having."

Uber also told CNBC that the company gave its drivers more control than any other private hire operator and many other forms of independent work, noting that there were no shifts or requirements to undertake a minimum number of hours.

A recent Oxford University study of 1,000 London Uber drivers found that 81 percent of drivers would prefer to remain independent contractors rather than lose the flexibility of setting their own schedule.

However, James Farrar, chair of the IWGB's UPHD branch, said drivers had been driven to industrial action by declining earnings and intimidation.

"After years of watching take home pay plummet and with management bullying of workers on the rise, workers have been left with no choice but to take strike action," he said in a press release. "We ask the public to please support drivers by not crossing the digital picket line by not using the app during strike time."

Uber will be facing the IWGB at the U.K.'s Court of Appeal on October 30 and 31.