Vauxhall is planning further fashionable small cars beyond the Adam three-door hatchback, but says it will not try to emulate the scale of the range offered by Mini.

Automatic and higher-performance versions of Adam are being openly talked about, and next year there will be a 115bhp three-cylinder 1.0-litre turbo engine similar to Ford's Ecoboost unit for the car.

At the Geneva Show next month Vauxhall will also show a concept car, Adam Rocks, giving clues as to how it could introduce a crossover or a convertible.

But there will be no two-seaters to rival the Mini Coupé and Roadster, and no larger model like the MINI Countryman. Nor will Adam be available with diesel engines because they would be too heavy and expensive, Vauxhall says.

Adamis pitched squarely at the Fiat 500 and Mini, and sits somewhere between them on price. The entry point is £11,255 for the base-trim model with a 1.2-litre engine, rising to £14,000 for the top-grade version with the more powerful of the two 1.4-litre power units.

Vauxhall claims a possible four billion personalisation combinations, including 60,000 exteriors, 80,000 interiors, 15 different trims and 20 sets of wheels - eventually to become 40.

Unique selling points include self-parking, printed and illuminated roof liners, a revolving programme of exterior colour packs which will be changed every year and connectivity to smartphones.

The car is being launched at the Westfield shopping centre next to the Olympic Park at Stratford, East London, where Vauxhall has opened a temporary Adam shop.

Vauxhall expects just over 8,000 UK sales this year, rising to an average of 10,700 a year from 2014. Nine out of 10 sales will be to private customers, with women expected to make up 60% of buyers.