Power may well be ‘the great aphrodisiac’, but was it the effortless 600bhp or the matchless quality of build and ride that made me love this car?

When Bentley announced the GTC (convertible) version of its ‘Speed’ Continental series of cars, there were some that felt the company had taken things too far. Cutting the roof off a coupé was – in days gone by – a recipe for disaster as it severely compromised the structural integrity. Bereft of sheet metal overhead, the finely tuned chassis no longer had the stiffness to make it work in the way its makers intended.

And so on (and on and on). In truth, car design nowadays is so sophisticated that modern convertibles from the boys that really know their stuff (193mph Ferrari F430 Spider a bit ‘soft’, anyone?) are truly excellent machines.

An open Bentley has, over the years, become a byword for luxury and a hedonistic lifestyle. In the early days, of course, the drophead coupés from the company's then-Cricklewood base were the high-performance models. A 'saloon' was just that: a well-built gentleman’s carriage for the chauffeur – or another car in the mews in addition to the owner’s sporting roadster.

The very name ‘Speed Model’ is one from the 1920s and represents a motor car fit for a more discerning sportsman, who liked his cars fast and elegant.

We drove the Continental GT Speed Coupé last year and were very impressed. This is a supercar that you can drive (and greatly enjoy) every day. My opinion would be that the all-round completeness of the car is an asset; not representing a soulless functionality found in many German über-saloons.

The GTC shares the coupé’s 6.0-litre W12. While 600bhp at 6000rpm is impressive, it’s the 553lb ft (750Nm) of torque from 1750-5600rpm that produces such astonishing performance from a 2485kg, 4wd 2+2 packed with powered everything. The car will top-out (‘top-up’, that is) at 200mph, and even with the roof retracted will achieve 195mph.

And, as with all Bentley’s performance statistics, you know that these figures are probably a little on the conservative side, too.

While we are talking power and performance, how about the cost-option Naim 1100W amplifier and 14 speakers fitted to the test car? The effect of this little lot on full chat is nearly as impressive as the sound of the twin rifled exhausts rumbling away in the background. The GTC’s insulated, three-layer fabric roof does let more of the ‘distant gunfire’ engine and exhaust noise into the car - no bad thing and another endearing aspect of the convertible version.

Hood up, the GTC is a little noisier than the coupé, with a bit of ‘swoosh’ making its way into the snug cabin. That said, travelling in a closed convertible is always something special. Considering the size (9.0J 20in alloys with 275/30 Pirelli P-Zeros) of the wheels and tyres, road thump and roar are impressively low.

Stylistically, the GTC Speed is almost identical to the regular convertible, updated in August 2007 when the first Speed-model coupés were introduced. Just a discreet bootlid spoiler announces that you’ve joined the fast set. From the side, roof up or down, it’s an attractive car and to my eyes better looking than the coupé.

Inside, though, and the open version of the car shifts from nearly-four-seater to simple 2+2. In the back, the headroom is possibly better - but the roof has to go somewhere and rear-seat passengers now have little legroom.

No such problem for the driver and front seat passenger, who will enjoy the standard Mulliner Driving Specification, diamond-quilted hide fully adjustable electric seats. As with the coupé, it does not feel a big car and can be easily placed on the road.

With the roof down, visibility is excellent, although you do occasionally have to watch the thick - for safety - windscreen pillars. Driving the car on a sunny day with the roof and all side-windows down is an exhilarating experience. The motor is just so strong and the traction so good that it can be launched from apex to apex at great speed but always in total security.

The excellent ZF six-speed automatic gearbox is in the right gear most of the time, although one downside of all these cars is that the column-mounted paddles are mounted slightly too high-up. They are also from moulded (rather than fabricated sheet) metal which makes for a bit of a fiddle when changing gear manually. You can use the gearlever in push/pull manual mode of course: but that’s not my preference.

The computer-controlled self-levelling air suspension all round is quite simply magnificent, allowing for the trademark Bentley ‘waft’ to mix with press-on driving worthy of any other 550+bhp supercar. You won’t get left behind by many cars on a reasonably open road – it’s so, so fast. And, compared to the equivalent Aston Martin or Ferrari, well priced, too.

Fuel consumption? Well, as a rule of thumb you will be looking at 16mpg or so - probably a little worse than the coupé.

You will notice the car’s registration: ‘BTU’. Whether this intentionally stands for ‘British Thermal Unit’ I could not say. But, British to its core, Bentley’s magnificent Continental GTC Speed represents power like no other.

The Bentley Continental GTC Speed costs £153,400 including ‘on the road’ charges in the UK. The test car was finished in Granite with Hotspur main hide and Beluga secondary hide.

Extras fitted included:

Contrast stitching £630.00
Alloy fuel filler cap £170.00
iPod interface linked to Infotainment System £280.00
Naim for Bentley Premium Audio System £4840.00
Power boot opening and closing £620.00
Reversing camera (in addition to standard ultrasonic park distance control front and rear) £4840.00
20in multi-spoke alloy sports wheels - dark tint finish £790.00
Dark tinted aluminium fascia panels and dark tinted aluminium centre console £6190.00

Text: Steve Wakefield
Photos: Classic Driver