The McLaren 720S Spider is the world's fastest convertible

Woking’s new Ferrari rival is fast in lots of ways, and not just at getting topless. We are used to McLaren convertibles giving little or nothing away to their coupe equivalents and the 720S Spider stays true to form. With a 49kg weight penalty, the 720PS (710bhp) Spider can still breeze from standstill to 62mph in a coupe-matching 2.9 seconds on its way to the same top speed of 212mph. In the 0-124mph test the Spider is a mere tenth of a second slower.

The less good news is that if you want to hit top speed with the top down you will be pegged back by 10mph. But then again it is still more than 200mph. How fast do you want to go with the wind in your hair?

McLaren Automotive says everything that’s good about Britain’s mid-engined supercar success in coupe form is carried over to the convertible, but allied to an all-new roof and rollover protection system that leaves that of its predecessor, the 650S Spider, looking a bit old hat.

The new roof is a one-piece retractable hard panel of carbon-fibre with an electric, rather than hydraulic, operating mechanism. McLaren says it is the fastest-acting of any supercar roof system, fully open to fully closed, or vice versa, taking 11 seconds at speeds up to 31mph. The 650S roof needed 17 seconds and wouldn’t work above 18mph.

It is also quieter in operation and, when in place, keeps enough hush in the cabin to make the new Spider quieter overall than its predecessor was as a coupe. As with the 650S Spider, the rear screen opens independently to reduce buffeting (and allow the V8 bark to fill the cabin, if so desired).

With the roof in place the silhouette is virtually the same as the coupe’s; with it down it works with the new frameless doors and glazed rear buttresses to present an appealing open cabin that impinges on neither the coupe’s all-round visibility or the body’s aerodynamic prowess. To keep airflow balanced, an active rear spoiler automatically alters its angle of attack depending on whether the roof is open or closed.

Did we mention that you can have this clever roof as a glazed electrochromic panel that turns translucent at the press of a button? You can, but it’s an option. Everything considered, McLaren is so chuffed with its new Spider’s roof that it has taken out global patents on it.

Central to all this is the 720S’s Monocage II carbon-fibre central structure that was designed from the outset to suit both coupe and Spider applications. As such it does not need any additional strengthening when missing its roof section, with even the A-pillars, already relatively slim in order to aid visibility from the driver’s seat, needing no extra reinforcement. The new ROPS (rollover protection system) is integrated into this structure and is all carbon-fibre now rather than the steel of the 650S Spider system, saving 6.8kg of mass.

Total dry weight of the new Spider is 1,332kg which McLaren asserts makes it the lightest in the topless supercar class, 88kg less than its closest competitor. McLaren says the combination of lightness and structural rigidity endow the Spider with exactly the same dynamic ability as the coupe, in the same way the only other Spider in the current line-up, the 570S, comes with no convertible compromises. The 4.0-litre twin-turbocharged V8 and  Proactive Chassis Control II hydraulic suspension with its three handling modes are all exactly as the coupe.

McLaren says this ensures the same depth of dynamic abilities as the coupe while at the same time ensuring its breadth of capability makes it just as everyday usable. Well, not quite perhaps. Clever though the new roof may be, it still takes up luggage space: the rear boot shrinks from 210 litres to 58 litres. The good news is the 150 litre front boot is unchanged.

Did anyone buy a convertible supercar for its luggage carrying ability? Unlikely. These are essentially cars to be seen in, and here the 720S Spider should keep everyone happy, with its new rear bodywork and those glazed buttresses making for a seamless marriage with the 720S’s already dramatic lines. Signature second-gen Super Series design cues like the ‘eye socket’ headlights and double-skinned dihedral doors are as evident as always. There’s a new 10-spoke forged-alloy wheel design and two new exterior colours – Belize Blue and Aztec Gold – plus the return of Supernova Silver which you may remember from the 12C.

Order now (prices from £237,000) and you could get one in time for spring 2019.