LONDON, England - Taxi drivers brought parts of London, Paris and other major European cities to a standstill on Wednesday (June 11 2014) while protesting against new private cab apps such as Uber which have shaken up the industry. Uber is also operating in South Africa.Thousands of London's black cabs, many blowing their horns, filled the roads around Buckingham Palace, Trafalgar Square and the Houses of Parliament and excluded all other vehicles.COMPLAINTS 'CRYSTALLISED'In the French capital, Paris, hundreds of drivers blocked access to the capital's two main airports and staged a "go-slow" during the morning 'rush hour'. Protests were also staged in Madrid, Barcelona, Berlin, Rome and Milan.STRIKE VIDEO: This was the scene on a freeway near Paris on Wednesday June 11 20143.Long-running complaints about competition from private-hire and unlicensed taxis have been crystallised by the new challenge posed by smartphone-dependent car services which use smartphone apps to call for private vehicular transport.California-based company Uber is the main target of the drivers' ire. Its increasingly popular app is used in 128 cities in 37 countries. It allows people to order and pay for a car using a cellphone with geo-locating technology connecting them to the nearest driver.Unlike other private-hire cabs - those that must be booked - Uber drivers use the app to fix the fare rather than it being calculated by a central operator.Critics say this amounts to a meter like those used by traditional London taxis and say Uber cars should be subject to the same tough regulations.PUBLICITY BACKFIRESGlenn Chapman, a 46-year-old driver parked in a long line of cabs outside Downing Street, where No.10 is the home of the incumbent prime minister, said: "We're governed by a set of rules and they don't seem to apply to Uber."The irony, of course, is that the protest has provided widespread publicity for the app and Uber has taken advantage by offering discounts while the strike lasts.Among those joining the protest were would-be drivers on mopeds who are learning 'The Knowledge', a detailed study of London street routes that every "cabbie" must complete (but is now largely outdated by computerised mapping).Chapman added: "The Knowledge took me two-and-a-half years but then all of a sudden anybody can jump in a cab and do our job."The London Licensed Taxi Driver Association, which predicted 10 000 cabs would join the protest, has lodged a legal challenge against the capital's Transport for London (TfL) authority to protest against Uber.NOT SAME TRAININGTfL chief operating office Garrett Emmerson urged the cabbies to wait for the outcome of a High Court case; "the demonstration is a pointless disruption".The London protest was joined by drivers across Europe, where the focus on Uber has re-ignited long-running disputes about the introduction of private-hire cab services. Critics say they are not subject to the same training, insurance and criminal checks as taxis licensed to pick up customers on the street.As such, they are able to undercut official taxis - a policy that has seen Uber fall foul of fares set by New York City's taxi commission.On Tuesday the Spanish region of Catalonia also warned it would fine any unauthorised Uber drivers as much as 8000 euros).Serge Metz, chief executive of French company Taxi G7, said: "Uber is deliberately not respecting regulations and on top of that has significant financial means."'STUCK IN DARK AGES'Uber was launched in 2009; earlier in June 2014 it was valued at $17-billion, one of the highest-yet for a technology start-up. Uber general manager Jo Bertram insisted, however, that the company's drivers had passed a "stringent and comprehensive" audit imposed by authorities in London.She accused taxi drivers of "being stuck in the dark ages".In London private-hire cars - also called minicabs - outnumber the traditional black cabs two to one. Over in France taxis are still fighting their existence, with limited success.Manuel Quina, a French taxi driver for five years, told AFP: "Clients should be able to choose their own mode of transport but the law must be respected."Rome taxi drivers are planning "a reverse strike" by charging only 10 euros per trip to fall in line with competitors' prices.In Milan and Madrid taxi drivers staged a day-long strike; in Berlin hundreds of drivers parked as a protest. • Wheels24 says the traditional taxi drivers should face up to the fact that technology is changing all industries, from robot welders on vehicle production lines through newspaper production which has cost thousands of jobs to the internet and email which has devastated traditional postal services. What do you readers have to say?Tell us in the Readers' Views section below or email us.