Nine months after the U.K. Supreme Court made a crucial decision that effectively forced Uber Technologies Inc. to provide worker rights for its drivers, the firm is back in court accused of trying to undermine the judgment.

Uber has challenged a small part of the landmark ruling, where a judge’s comments suggest the tech firm should enter into a direct contract with passengers when providing car journeys. The ride hailing-app is seeking a ruling that, that isn’t the case, which it argues is in line with the London transport regulator’s guidance.

“I thought the Supreme Court ruling was the end of the matter but just months later we are being forced back to court to defend this landmark ruling from Uber’s army of slick corporate lawyers who are determined to strip us of our rights,” Yaseen Aslam, president of the the App Drivers and Couriers Union and the lead claimant in the Supreme Court case, said.

Earlier this year, the nation’s top court ruled that Uber must treat its drivers as “workers,” giving them access to vacation pay, rest breaks and minimum wage while they’re using the app. Just weeks later, Uber said it would reclassify all its U.K. drivers as workers and later announced it had formally recognized the GMB labor union, giving drivers increased powers to collectively bargain.