Toyota is the latest brand to offer a stop-start petrol engine.
The 101PS 1.3-litre engine, fitted in the Auris, offers economy of 48.7mpg, an improvement of 19% over the outgoing 1.4-litre engine, and emissions of 135g/km, a 17% improvement. A new six-speed gearbox also makes its debut.
The stop-start technology, dubbed Toyota Optimal Drive, will extend across the Toyota range, starting with the iQ, Avensis and Auris.
