BEFORE the Mini sets out to conquer new territory by launching three radical new models, the boffins at Bavarian Motor Works have been quietly tweaking the performance of all its existing Minis to offer a bit more “ooomph” for potential new buyers of the hugely popular car.

The outcome of all this Teutonic tinkering, dubbed “more poke with less smoke” by the Mini marketing men, has seen the carmaker ditch its 1.4l engine and replace it with a beefed-up 1.6l version to make one of the world’s zippiest little motors even quicker on the trigger.

The results are a welcome shot in the arm for both the Mini Cooper and the Mini Clubman.

However, the main beneficiary of all the jiggery pokery under the bonnet is the new Mini One, which for the first time has also had its hardhat lopped off by the BMW design team and replaced by an all-electric soft top, making it the cheapest convertible Mini on the market.

During yesterday’s launch event, BMW bosses joked about introducing their last Mini convertible in the middle of winter.

However, there were no such mistakes yesterday as the firm pulled the covers off its latest muscular munchkin and was rewarded by rays of sunshine.

After taking a new pepper white convertible out for a 20-minute spin, I soon got the feeling that the cabriolet could be Mini’s nimblest little minx to date.

There are few surprises in the interior, the Biggles-style switches are all present and correct in the central console while, the huge, ubiquitous speedometer still glares out at you like an oversize pop Swatch.

But after producing such a successful brand, evolution not revolution is the watchword at Mini, so while the tangible improvements can seem slight, it is hard to put a price tag on the improved driving experience offered by putting the One’s top down and feeling and hearing the response of the new 98BHP engine.

With the ability to propel you from 0-62mph in 11.3 seconds, two seconds quicker than before, drivers are invited to put their foot down, and the road-hugging traction and solid build quality gives you the kind of thrill you might get from driving a gold plated go-kart.

Small and compact, the Mini One is effectively only a two-seater but for £14,985, almost £1,500 cheaper than the genuine four-seat Cooper convertible, the One is a bachelors’ dream.

However, bean counters can also afford a little smile as workers at the BMW factory in Hams Hall, Warwickshire, have also squeezed more fuel economy from the engine, improving it from 44.4mpg in the old 1.4l to 49.6mpg with the new 1.6l With a new Coupe, Roadster and Countryman in the offing, the sun still hasn’t set on BMW’s new-fangled Mini.