Traffic in central London is expected to be severely disrupted on Wednesday as up to 12,000 taxi drivers converge on the capital to protest against the American taxi-hire company Uber.
Streets around Trafalgar Square will be paralysed from early afternoon by a demonstration that is also expected to attract taxi drivers from France and the Netherlands.
San-Francisco based Uber, backed by heavyweight investors including Goldman Sachs and Google, allows customers to book and pay for a taxi using an app on their smartphones. It also provides a second app for drivers to calculate the cost of a journey.
But drivers of London's iconic black cabs say this second app amounts to a taximeter and legally violates industry regulations. Whilst the city's 25,000 black cabs can be flagged down in the street and use a meter to calculate fares, the 44,000 private-hire minicabs must be pre-booked with a set fare and destination.
Transport for London (TfL), which regulates the capital's various transport systems, has asked the High Court to rule on the legal issue.
TfL's chief operating officer for surface transport Garrett Emmerson said: "A number of taxi drivers are set to cause pointless disruption for Londoners over a legal issue that is down to the Courts to decide upon."
However, drivers groups and unions say the protest is also directed at London Mayor Boris Johnson for what they call "an-all out assault" on their industry.
Under the banner "Cabbies Against Boris" they are protesting a rule aimed at reducing road pollution which bans the use of taxis which are more than 15 years old. They say the ban has done nothing to decrease pollution levels and forced drivers to needlessly spend money on new taxis, which cost up to 40,000 pounds each.
"There will be serious disruption on Wednesday," said Mick Cash, acting general secretary of the RMT transport union. "But that will be nothing compared to the disruption and dangers of allowing our licensed taxis to be driven from our streets through a combination of ignorance and greed."
TfL recommended using the Tube or walking in central London.