Cabbies are to find out the result of a High Court challenge which, if successful, could disrupt completion of London Mayor Boris Johnson's £47 million flagship east-west cycle superhighway.
The Licensed Taxi Drivers Association (LTDA) has asked a judge to declare that the continued construction of the segregated cycling route linking Westbourne Grove and Tower Hill via the Victoria Embankment without planning permission "constitutes a breach of planning control".
Steve McNamara, LTDA's general secretary, has accused Mr Johnson of rushing through the scheme as an ill-judged "last hurrah" before he leaves office.
The cabbies say the scheme is already causing massive, disruptive traffic delays in central London because of the amount of road space it is taking up.
The LTDA asked Mrs Justice Patterson at a recent hearing in London to grant a judicial review against Transport for London (TfL) and the Mayor to force a reconsideration of the whole project.
The judge is announcing her decision on Wednesday. Although she heard the dispute in London she is giving her ruling in Birmingham where she is currently sitting.
When the legal challenge was first announced, many cyclists threatened on Twitter to withdraw their custom from black cabs, and some said they would use rival Uber instead.
Howard Carter, general counsel at TfL, said "the east-west cycle superhighway will make London's roads safer for all, particularly cyclists".
TfL is the highway authority for all Greater London Authority (GLA) roads. Its legal team argued that it would be "inappropriate" for the court to make a declaration as it would usurp the powers of local planning authorities.
Timothy Straker QC, appearing for TfL, also contended that the application had been made too late and is academic - and in any event the construction of the cycle superhighway does not require planning permission.