The Austin FX3 London Taxi cab was introduced in 1948 and went into full production in 1949 which ended in 1958.

It had a 2.2-litre ohv petrol engine and was fitted with an all-steel body from Carbodies. It had a traditional 3-door body, with an open luggage platform rather than a front passenger seat beside the driver. It FX3 was fitted with mechanical brakes, with rod operation, beam axles on leaf springs and a built-in Jackall hydraulic jacking system. The petrol engine proved expensive to run, and diesel engines from Standard and also Birch Brothers were used. Austin eventually produced a diesel engine in 1956.

Like all London taxis, it has a tight turning circle of 25 ft (7.6m) diameter, as required by the Conditions of Fitness.