BMW 420d SE Convertible, £36,675
Engine: 2.0-litre diesel unit producing 184bhp and 280lb/ft of torque
Transmission: Six-speed manual driving the rear wheels
Performance: Top speed 146mph, 0-62mph in 8.2 seconds
Economy: 55.4mpg combined
Emissions: 133g/km of CO2

IN a parallel universe this car would still be called a 3 Series, but BMW has shaken up its naming conventions and the two-door 3 Series is now the 4 Series.

Tested here in convertible guise, the roofless 4 Series aims to blend the sophistication of the coupe variant with the glamour of open top motoring.

The initial signs are good, thanks in part to the convertible’s powered metal roof and the familiar cabin environment boasting all the usual BMW mod cons, ample space for two adults and a pleasingly premium ambience when the roof is up.

Looks and image Mirroring the tin-top variant from the waist down, the 4 Series Convertible boasts the same rakish nose and sleek profile.

Thankfully the inclusion of a metal folding roof hasn’t harmed the car’s rear, which remains as streamlined as that of the coupe despite having to accommodate the roof.

The cool, sophisticated look continues inside the 4 Series, with an understated cabin design that can be tailored to your taste with a wide array of different trim and colour combinations. Make no mistake, this is the real deal when it comes to premium drop-top motoring. The classy cabin and distinctive exterior design combine to generate considerable kerb appeal.

Space and practicality The BMW might have four seats but the reality is somewhat different; with two adult occupants up front, legroom in the back is pretty tight. Add a wind deflector and you’ll probably want to pass on offering lifts to friends – even if it’s only a short hop to the pub. Elsewhere, parallels with a 3 Series are obvious: ample space up front, plenty of oddment storage options and a surprisingly accommodating boot. Key to this is the ability expand the loading aperture if you need to reach inside. It’s an extension of the power fold mechanism when the roof is down and is a simple button press.

Behind the wheel Talk about being able to have your cake and eat it. With this 420d diesel variant the 4 Series Convertible suddenly becomes easier to justify – be that to a sceptical partner or your company’s fleet boss. Modest emissions and fuel consumption from the 2.0-litre diesel motor means you can make meaningful savings while getting a suntan.

Thankfully BMW’s diesel engines are pretty quiet, and in this 420d it’s only when driving hard do really know that you’re driving an oil-burner. For the rest of the time you can exploit the engine’s ample torque, ensuring a relaxed and agreeable approach to motoring. Weighty controls and a firm but measured ride allow for brisk progress when you’re in the mood.

Value for money It’s all relative at this end of the market, but the added diesel angle here does ensure you get to keep more of your cash in the long term. A low tax band plus the 420d’s frugal performance should see a positive change to your personal bottom line, although you might want to get familiar with the options list -standard specification is modest and there are some items worth picking that genuinely add value to the premium motoring experience.

Who would buy one?

Anyone seeking the full roof down experience for sensible money would be wise to have the 4 Series Convertible on their shopping list. Of the three big German brands, the BMW is probably the most engaging to drive, while in diesel form you gain a few more pounds in your pocket. Understated yet classy, this drop-top 4 Series is a rounded performer offering style and practicality in equal measure.

This car summed up in a single word: Understated If this car was a…: dress code for an interview it would be smart casual – classy yet understated.