Here's how to celebrate Mini’s 50th birthday in style! Alongside the MINI Coupé Concept, parent firm BMW has surprised visitors to the Frankfurt Motor Show with a bonus unveil – a stunning Roadster version.

Designed to mark the brand’s half-century, the two-seater Roadster Concept takes MINI further into new territory. And it gives drivers in the market for the Audi TT Roadster, BMW Z4 or Mazda MX-5 another highly desirable model to consider.

As with the low-slung Speedster variant we revealed in Issue 1,060, the drop-top is a real head-turner. It takes MINI’s instantly recognisable design and makes it sportier. Plus, like the Coupé, it’s even more focused and fun-to-drive – but with an open roof.

The front end shares much with the Cooper S, such as its bold headlights and chrome grille. Below those lies a wider, more aggressive splitter, while the A-pillars are steeply raked to give a more aerodynamic look.

There’s no metal hood – instead, the covering is made of fabric, and it’s manually operated. This is a much lighter solution to a fully electric mechanism. Much like an MX-5’s hood, it is folded simply and neatly behind the occupants’ heads.

The arrangement makes the Roadster surprisingly practical. Regardless of whether the roof is raised or lowered, there are 250 litres of luggage space.

Under the bonnet lies the same engine as in the Cooper S – a 175bhp 1.6-litre turbocharged four-cylinder petrol unit. It produces 240Nm of torque, but can generate 260Nm for short periods during overboost.

While official performance figures have yet to be released, we expect the Roadster to cover 0-62mph in seven seconds and accelerate on to 140mph.

There’s no on-sale date yet, but both the Roadster and Coupe version ae expected to make it to in showrooms by 2011.

Also flanking the two new concepts were the MINI Mayfair and Camden special editions, first revealed to the public at the firm's 50th birthday bash - the MINI United festival hosted by Silverstone.

Mini Roadster out in open