Central London will be brought to a standstill on Wednesday by a procession of 10,000 black cabs protesting against the mobile app Uber.
Transport for London (TfL) has warned of significant traffic disruption in the capital as taxi drivers gear up to take on the rival cab service.
The Licensed Taxi Drivers Association has helped to organise a protest which promises “severe chaos, congestion and confusion across the metropolis”.
Police have moved to try to avoid travel chaos in London during the protest by imposing conditions on the demonstration - much to the fury of drivers.
Thousands of black cab and licensed taxi drivers will block roads for hours today after driving slowly through the capital from Trafalgar Square.
The row has flared over the introduction of a phone app called Uber which allows customers to book and track vehicles.
The Licensed Taxi Drivers Association argues that Uber acts like a taxi meter, which private cars are not allowed to use and has warned that the move is leading to unlicensed drivers being contacted via the new technology, with no checks on whether they are legitimate.
It is thought that up to 10,000 drivers will mass on Trafalgar Square at 2pm tomorrow. Rival app Kabbee claims that the disruption will cost the economy £125m.
The Metropolitan Police said that "repeated attempts" to get the organisers of the demonstration to have a constructive discussion had failed.
Chief Superintendent Pippa Mills said: "We have attempted to contact those who we believed to be responsible for organising this event.
"We even put out a letter through our social media channels to encourage organisers to come forward but they have either ignored our approach or been misleading.
"As a consequence and in order to prevent serious disruption to the life of the community we have been left with no option but to impose conditions on the demonstration.
"Breach of these conditions constitutes an offence under Section 14 of the Public Order Act 1986 and may render the individual breaching the conditions liable to arrest."
But Mick Cash, acting general secretary of the Rail, Maritime and Transport union, said it is "shocking that taxi drivers protesting in defence of their trade should be threatened with blanket arrest."
"RMT is calling on the police to lift this draconian warning and the threat to criminalise the entire licensed taxi industry," he added.
"This protest is about the ripping up of established metering and hire regulations in the name of greed and private profit and the decimation of London's black cabs."
Police said the demonstration must not start before 2pm and must not end later than 3pm. Conditions were also set on the maximum number of people allowed to assemble.
"When the area is congested no further persons will be allowed to join the demonstration. It will be the tactical commander of the event that will determine when the area is congested," said police.
Steve Garelick of the GMB union's professional drivers branch, denied the police had contacted him. "Why the police have issued this statement baffles me," he said.
Legal action is being taken against Transport for London (TfL) but drivers are taking direct action, starting with today's protest. Motorists have been advised to avoid central London during the protest.
London Mayor Boris Johnson said he understood the concerns of taxi drivers but added that the issue should be resolved in the courts.
He said London's black cab trade was crucial to the fabric of the city, adding: "The hackney carriage is iconic, and it is absolutely right that our cabbies are properly protected.
"Indeed it is enshrined in law that only black cab drivers have the right to be hailed from the street, and that principle, the bedrock on which our black cabs operate, will never change.
"Black cab drivers are the face of London not just for Londoners but for millions of visitors to our city. Their licence is dependent on passing 'the knowledge' - years of hard graft go into learning every street name, and memorising every conceivable route across that city. That knowledge is why people choose to use black cabs.
"There must, however be a place for new technology to work in harmony with the black cab, and we shouldn't unnecessarily restrict new ideas that are of genuine benefit to Londoners.
"Even so the recent emergence of a range of new apps has raised some important questions in relation the operation of the private hire and taxi trades."
