The new range of Cowley-built Minis will be completed in March when the latest models are unveiled at the Geneva Motor Show.

The Mini One will be the base model with a 1.4 litre engine and on the road price of £11,595.

It will be joined by the diesel-powered Mini Cooper D with a 1.6 litre engine that will cost £14,190.

Both cars will make their debut at the motor show on March 8 before going on general sale in April.

The Mini One has a top speed of 115mph and can go from 0-60mph in 10.9 seconds.

The vehicle can do nearly 50 miles to the gallon - 15 per cent better than the old Mini One.

And its diesel stable mate produces an even better figure, producing 64.2 miles to the gallon. It has a top speed of 121mph and can can go from 0-60mph in 9.9 seconds.

The arrival of the two models follows the launch of the new Mini Cooper and Cooper S which went on sale last November. By the end of 2006 nearly 7,000 orders were taken for the new models in the UK alone.

Unlike its predecessor, the Mini One D, which had limited sales, production figures for the Cooper D will be driven by customer demand as it has an engine jointly produced by parent company BMW and PSA Peugeot Citroen.

The diesel engine is built at the PSA Douvrain plant near Paris while the petrol version is produced at Hams Hall in the Midlands.

Spokesman Mark Harrison said the Mini Convertible will continue in its current "old" form until at least 2009, although the engine will be replaced with the modern version in due course.