Rover’s fourth gas turbine prototype, the T4, continued an innovative programme to develop alternative fuel systems, but this was to be their last experiment for passenger cars.

The T4 was the closest Rover got to an on-the-road gas turbine car. It used a Rover 2000 (P6) prototype body shell which had a modified nose and, unlike the T3 of 1956, a 2S/140 turbine engine mounted at the front driving the front wheels. It had independent rear suspension with swing axles and there was hope that it would reach production.

Rover claimed it could be produced in three years if the market was ready and could be sold for £3,000-£4,000, even though the most expensive Rover at the time cost £1,948. Confidence was such that the production version of the Rover 2000 was designed to be able to accommodate a gas turbine option under the bonnet through an unusual front suspension layout.

Rover decided to abandon any plans of mass producing a gas turbine engine, however, long before the 2000 was released. Manufacturing costs were simply too high and fuel consumption continued to be a problem at 16-20 miles per gallon.