TfL and Uber had both argued at a one-day hearing earlier in October that the app was not a meter, and both organisations greeted the decision as a victory.
The Licensed Taxi Drivers’ Association (LTDA), which represents many of the 25,000 licensed taxi drivers in London, asked the judge to rule it was a meter and ban its use.
LTDA chairman Richard Massett said: “We certainly are going to an appeal.
“It’s a fact that the smartphone acts in exactly the same way as a taximeter. It calculates the fare by means of time taken and distance covered – and it’s doing exactly the same job.
“Private hire legislation specifically precludes private hire from using a meter – and that’s exactly what it is.”
The Licensed Private Hire Car Association (LPHCA) backed the LTDA and said the app was “an attempt to circumvent the statutory prohibition” on minicabs using meters.