The FX4 had a distinctive, purpose-built design for use as a taxi. It featured a high roofline to provide ample headroom for passengers and a spacious interior. The front grille and overall shape were characteristic of the classic London black cab.

The FX4 initially had a four-cylinder petrol engine. However, later models were often equipped with a diesel engine for better fuel efficiency.

The FX4, along with other classic London taxis, played a significant role in the city’s cultural identity. The sight of a black cab became synonymous with London itself.