In London, the age limit for Hackney Carriages (traditional Black Cabs) is strictly regulated by Transport for London (TfL) to manage air quality and vehicle safety. As of 2026, the maximum age for a traditional diesel-powered taxi is 12 years, down from the previous 15-year limit as part of the city's "Ultra Low Emission Zone" (ULEZ) initiatives. However, for the new zero-emission capable (ZEC) taxis, such as the LEVC TX electric models, the age limit remains 15 years. TfL enforces these limits by refusing to renew the vehicle license once the age threshold is reached, regardless of the vehicle's mechanical condition. This policy has effectively accelerated the phasing out of older, iconic models like the LTI TX4 in favor of quieter, more environmentally friendly hybrid and electric versions. For passengers, this means that the fleet of London cabs is one of the most modern in the world, though it has put significant financial pressure on drivers to upgrade to expensive new electric models to stay within the legal operating window.