The TX4 was introduced as an updated model in the TX series, succeeding the TX2. It continued the tradition of the iconic London black cab design. The TX4 featured a diesel engine, addressing environmental concerns and complying with emission standards.

Like its predecessors, the TX4 was designed to be wheelchair-accessible, ensuring inclusivity for passengers with mobility needs. The TX4 incorporated safety features and modern technology, reflecting advancements in vehicle design and functionality. Durability and reliability were emphasized in the design of the TX4, considering the demanding nature of urban taxi use.