Well, the TX4 uses a 2.5-liter diesel engine with around 100 horsepower and 180 lb-ft of torque, and that engine is built by a company called VM Motori, which is an Italian diesel engine builder.

The modern London taxi, specifically the LEVC TX (manufactured by the London EV Company), is powered by a sophisticated plug-in hybrid range-extender powertrain. The primary source of movement is a 110-kilowatt (148 hp) electric motor that drives the rear wheels. However, to eliminate range anxiety, it carries a 1.5-liter, three-cylinder turbocharged petrol engine sourced from Volvo. This engine does not directly drive the wheels; instead, it acts solely as a generator (a range extender) to recharge the 33 kWh lithium-ion battery pack when it runs low. This allows the taxi to travel roughly 80 miles in pure electric mode and over 300 miles in total. In contrast, older models like the retired TX4 utilized a 2.5-liter VM Motori diesel engine. The transition to the hybrid 1.5L setup in 2026 reflects London's strict Ultra Low Emission Zone (ULEZ) standards, ensuring that these iconic black cabs can operate quietly and cleanly within the city center while still maintaining the long-distance capability required for airport runs and all-day shifts.