UPDATE 1-Uber must do more on UK minimum wage pledge -union

Adds background, business minister

By Costas Pitas

LONDON, March 16 (Reuters) - Uber UBER.N drivers in Britain should receive the minimum wage from the time they log on until they log off from the app, two former drivers who led a successful court battle said after the firm granted workers' rights on Wednesday.

Following a Supreme Court defeat last month, the Silicon Valley-based company reclassified its more than 70,000 drivers in Britain as workers, meaning they are guaranteed entitlements such as holiday pay. nL1N2LE2PP

On the minimum wage, which stands at 8.72 pounds ($12.13) per hour for those aged 25 and over, Uber said it would apply "after accepting a trip request and after expenses" and that on average drivers earn an hourly 17 pounds in London.

Drivers will not receive it during the time they spend waiting for a passenger, which can account for as much as a third of the time drivers are behind the wheel with the app turned on, according to several U.S. studies.

James Farrar and Yaseen Aslam, the two lead drivers in a 2016 employment tribunal case that Uber unsuccessfully contested all the way to Britain's top court, criticised the move.

"Uber drivers will be still short-changed to the tune of 40-50%," they said in a statement released by the App Drivers & Couriers Union.

"Also, it is not acceptable for Uber to unilaterally decide the driver expense base in calculating minimum wage."

Uber said it has consulted with thousands of drivers over the last few weeks who do not want to lose the flexibility they enjoy, with the ability to choose "if, when and where they drive."

Workers are entitled to fewer rights than those classed as employees, who are also receive sick pay and parental leave. Uber in California last year pushed and won a similar compromise on drivers' status.

The announcement could put pressure on other firms operating in the gig economy, where millions of people tend to work for one or more companies on a job-by-job basis.

"The new phase of our economy should be about protecting workers' rights, driving higher standards, driving new technologies," business minister Kwasi Kwarteng told Sky News.

($1 = 0.7191 pounds)

(Reporting by Costas Pitas; editing by James Davey and Louise Heavens)

((Costas.Pitas@thomsonreuters.com; 0207 513 4700; Reuters Messaging: costas.pitas.thomsonreuters@reuters.net and @Cpitas on Twitter))