Thousands of taxi drivers brought part of central London to a standstill in protest at rival service Uber – a mobile phone app, BBC reported.
Cabbies gathered at Trafalgar Square for an hour-long protest.
The drivers are angry about what they regard as a lack of regulation of the use of apps such as Uber.
The app works out the cost of journeys and cab drivers say it is the same as using a taxi meter, which only black cabs are legally entitled to use.
The Licensed Taxi Drivers Association (LTDA) also said part of the demonstration was about highlighting the length of training – between four and seven years – that taxi drivers undergo before being licensed.