Black cabs surrounded Parliament Square on Wednesday afternoon in an ongoing dispute over the closure of a busy junction to traffic.
Scores of taxis descended on Millbank as part of a week-long action over a traffic ban at Bank Junction.
Roads were blocked around Parliament from 3pm as the demonstration caused gridlock.
Photos also showed crowds of vehicles packed into nearby Smith Square nearby.
It comes after the City of London Corporation approved plans to ban cars, taxis and lorries from Bank Junction from 7am to 7pm to improve safety.
The scheme, set to start in April, will see only cyclist and buses able to use the junction for 18 months.
Wednesday’s demonstration came following two successive days of action in the capital, with similar scenes at Bank Junction on Monday and a rolling protest through the City on Tuesday.
Cab drivers have threatened to continue their protests every day this week.
