The taxi drivers have said the protest, which is due to reach the Portuguese parliament building later today, will not end until the government agrees to shut down the alternative public transport services, which they say is not covered by the law.

The platforms, which in Portugal include Uber and Cabify, allow any car to pick up passengers through a smartphone app, but the drivers of those cars are not required to meet the same standards as official taxis.

The new law announced by the government at the end of September includes requirements for Uber drivers and similar to have 30 hours of training (taxi drivers have 150) and a special license. The vehicles must be less than seven years old (almost all Uber cars are much newer and many taxis are much older) and they must have similar insurance to taxis and issue electronic receipts.

Some 6,000 taxis from across the country were due to drive slowly across the city bringing chaos to traffic in the Portuguese capital. The riot police have been deployed as a preventative measure.