London's black cabs have promised to bring "chaos, congestion and confusion" to London as a protest against the growing presence of smartphone taxi service Uber.
The Licensed Taxi Drivers Association (LTDA) has said that the apps that Uber's drivers use to find passengers and calculate their fares count as taximeters - devices that are illegal to be installed in private vehicles.
The LTDA has complained to Transport for London (TfL), but the government body has said that Uber's vehicles are not "equipped" with taximeters since there was no "connection between the device and the vehicle".
LTDA have rejected this evaluation and are threatening to seek a judicial review with Steve McNamara, the association's general secretary, describing the situation as "dangerous for Londoners".
Mr McNamara told the BBC that London's black cab drivers were planning to gridlock in the city sometime in early June.