The engines, which will be known as ECOTEC diesels, are a 2.0 litre direct injection 82 PS16v unit which will make its debut in the Vectra late this year. That will be followed, probably in a year's time, by an intercooled 100 PS variant of the 2.0 engine and a 120 PS 2.2 litre unit 16v.

While Vauxhall says the engines will eventually be offered in six model ranges, installed longitudinally and transversely in front, rear and four-wheel drive vehicles, it has yet to announce which models. Similarly the manufacturer has yet to decide the future of its Isuzu-produced 1.7 TD engine currently used in the Astra and Vectra.

The direct injection four valves per cylinder is an industry first and marks a £227 million investment by the manufacturer in a new German plant. In the Euromix test cycle the 2.0 DI 82 PS engine achieves 57.7 mpg (or 47.9 mpg according to the new European test method which includes cold starts), which adds up to a 17% improvement over the current Isuzu-based 1.7 TDS indirect injection turbodiesel with the same power output. Exhaust emissions are claimed to be 20% below the EU 96 standard. Service costs will also be reduced as the new diesel engines require an oil change after 10,000 miles or once a year - the same as their ECOTEC petrol engine cousins.