Mini could grow from a seven model line-up to "eight or 10" thanks to the flexibility of the new architecture for the next generation set to go on sale next spring after its unveil in November.

"We have to be very careful how we develop the product portfolio and the Mini brand," said Peter Schwarzenbauer, board member with responsibility for Mini, Rolls-Royce and BMW Motorrad, the motorcycle division.

"We're defining the long-term portfolio and asking what the image of Mini will be in 2020," he said.

The new architecture allows for the Mini range to stretch in length from 3.8 metres to 4.5 metres.

"But we have to respect Mini's heritage," he said, adding that the reason the variants have become bigger is in response to customer feedback.

The hatch and the Countryman are the best sellers in the range globally, taking about one-third each of total sales leaving another third to be split between the five other models.

Global sales are around 300,000 and with production now at three facilities - Oxford, Magna in Austria and NedCar in the Netherlands - there is the potential to grow further "but I'm not a fan of putting big numbers out," he said.