For once, here’s a Geneva show ‘concept car’ that is just that; a genuine, not-for-production fantasy model, rather than the so-called ‘concepts’ of so many recent years – pre-production examples of soon-for-volume-production models tarted up into so-called ‘concept’ versions in a seemingly desperate attempt to court press day publicity.

BMW-owned Rolls-Royce Motor Cars unveiled the ‘experimental’ 100EX on Tuesday. The car (the blurb says: “There is no plan to produce the 100EX as a series model”) was designed to celebrate the 100th anniversary of the marque, on May 4. It will appear at various events throughout 2004 to help mark the centenary.

Based on a lightweight aluminium spaceframe, the 100EX is an open-top, four-seat, two-door drophead (that’s a posh way of saying ‘convertible’) and is the first experimental motor car to be produced by Rolls-Royce under BMW since the launch of the all-new Phantom in January 2003.

A notable feature is the rear-hinged ‘suicide’ front doors (dubbed ‘coach doors’) that safety regulations would probably rule out should Rolls-Royce change its mind and put the car into production.

A polished aluminium waist rail surrounds the passenger compartment, set off against dark curzon paintwork. Those rear-hinged doors are said to give ‘exceptional’ access to the rear seat.

The bonnet and windscreen surround have both been milled from solid blocks of aluminium before being hand polished and the traditional silver lady mascot sits atop the grille.

Bleached teak decking is used on the exterior and interior of the 100EX, notably on the tonneau cover, in the boot and in place of carpeting in the passenger cabin. “The overall impression is intended to be of an elegant motor yacht at speed”, said R-R’s chief stylist Marek Djordjevic.

The rear of the car tapers into a boat-tail style and features the ‘countryman’ boot, split to give a separate lower tailgate which, when down, provides a completely flat surface, ideal for picnics or as an elevated platform with its inlaid fibre matting.

A tailored soft top made from a new advanced material, featuring fine metallic threads, protects passengers from the elements. Inside, the hood is lined with the familiar cashmere/wool blend fabric seen in the Phantom. Painstaking design of the folding mechanism means the hood can be concealed in an extremely small storage area, keeping intrusion into the luggage and passenger space to a minimum.

Figured mahogany is used inside, complemented by a special metallic finish which is used in a swathe across the dashboard and in the finer detailing. Sculptured seats are finished in rich dark curzon leather, with additional leatherwork in contrasting aniline tan.

Suspension and steering geometry are shared with the new Phantom: double wishbone front and multi-link rear axles, with air springs, and rack and pinion steering though it is shorter by 165 mm (6.5 in) and 71 mm (3 in) lower. The 100EX rides on 21-inch wheels finished in meteor silver.

Power is from a nine-litre V16, 64-valve naturally aspirated engine, no doubt of ‘adequate’ output, in keeping with a long-standing Rolls-Royce tradition of not revealing horsepower figures, except under regulatory duress.

Speaking at the Geneva Motor Show, Rolls-Royce Motor Cars chairman and CEO, Tony Gott, said: “It is always exciting to unveil something new at a motor show, but particularly something as fresh and innovative as the 100EX. In wanting to mark this very special year we decided that there would be no better way than to revive the EX motor cars philosophy and produce something unique to show around the world.”