Class in glass

To do so, it needed to minimise the usual compromises associated with compact open-top cars sporting four seats, paying particular attention to practicality, driving dynamics and integrating a bulky roof mechanism without sabotaging the styling. Not an easy task.

It seems that after a decidedly shaky start, we're getting there with folding hard-top convertibles. The idea can be traced back to the 1930s, as Renault's rivals at Peugeot never tire of reminding us, but it's much more recently that the technology has started to become commonplace on vehicles with mainstream price tags. The best exponents to date have been two-seater roadsters but the presence of a solid roof big enough to cover a genuine four-seat cabin is much more problematic for designers - especially at the accessible price-point where Renault's Megane operates.

Early folding hard-top models like the Peugeot 307CC and the previous generation Megane Coupe-Cabriolet placed major restrictions on rear passenger and boot space. They also tended to look rather rotund around the hindquarters and you could really feel the extra weight in action when you stomped the throttle or pitched the car into a corner. In time-honoured fashion, the leading manufacturers have been busy learning from past mistakes and the modern Megane Coupe-Cabriolet should give a good indication of where they're at.

There's a choice of petrol and diesel engines available to fill the engine bay of the Megane CC. These range from a 110bhp 1.6-litre petrol to a 160bhp 2.0-litre dCi diesel. Renault's impressive TCe (Turbo Control efficiency) technology is employed in the 130bhp 1.4 TCe unit and there's a couple of interesting options for those who'd prefer an automatic.

The conventional 140bhp 2.0-litre petrol engine can be mated to a smooth shifting CVT gearbox and the entry-level 110bhb dCi diesel is available with Renault's clever EDC twin-clutch auto.

Some hard-top convertibles set out to disguise the fact that the roof is removable through their styling but the Megane Coupe-Cabriolet intentionally looks like an open topped-car whether the hood is up or down. When raised, the glass roof forms a bubble over the cabin bringing extra illumination and an airy feel to the interior. The translucent glasshouse gives the car a bottom-heavy appearance for a more purposeful stance on the road.

At the touch of a button, the roof breaks apart and begins its balletic decent into the confines of the boot. 21 seconds later, the Megane CC is an elegantly proportioned convertible. The windscreen is forward to maximise cabin space and aid access through the car's two doors. It's also designed to work in conjunction with the fixed glass wind deflector behind the rear headrests to reduce air flow through the cabin at speed. Elsewhere, the interior design is similar to the Megane hatchback models with the same classy materials on display.

The boot is only 211 litres with the hood lowered but rises to 417-litres with it raised and access to this luggage area is enhanced both by a wide aperture and a low sill height 590mm from the ground.

Renault's usual raft of technology and safety features is featured in the Megane Coupe-Cabriolet. Depending on the model, there's the Renault keycard keyless entry and start system, dual-zone climate control, an Arkamys 3D sound stereo system and the Carminat TomTom satellite navigation technology. Safety kit is also generous with ESP stability control fitted as standard along with a full complement of airbags.

The car is also designed to protect occupants in the event of a roll-over with specially reinforced windscreen pillars and body structure.

Folding hard-top cars are widespread these days and there's a select group of vehicles that the Megane CC will need to face down if it's to win the battle for sales. The Peugeot 308CC is probably the key rival. Then there's the Ford Focus CC, the Volkswagen Eos and more expensive premium-brand models like the Audi's A3 Cabriolet and the BMW 1 Series Convertible.

All of the diesel engines in the Megane Coupe Cabriolet come fitted with DPF particulate filters to keep a check on emissions. Despite the extra weight of this convertible model, economy shouldn't be a million miles away from what's achieved by Megane hatchbacks with the same engines. The automatic gearbox options are designed to bring minimal fuel consumption penalties.

Affordable folding hard-top cars used to ask some pretty big sacrifices of their owners. Today's models are beginning to look and feel less like they're built around a hefty, complex roof mechanism and more like fully-developed cars in their own right. The signs are good for Renault's Megane Coupe Cabriolet with its well integrated folding glass roof, four-seat layout and great emphasis on preserving the driving dynamics of the Megane hatchbacks.