The Speedtail is a departure for McLaren in more ways than one. For one thing, it's the first time that the firm has opted to officially unveil a new model so far ahead of its launch. To illustrate just how long it will be before the 'hyper GT' enters production, McLaren took the unusual step of revealing one of the first development mules alongside what is, at most, a 30mph show car. Why? Because it is one of two test cars that will be making their way to the EuroTunnel next week as the next phase of on-road testing begins - and people are going to, you know, notice.
They're going to notice because the Speedtail is the most dramatic looking model to emerge from Woking, ever. Beauty is in the eye of the beholder, of course, but the fastest McLaren yet is 5.2 metres (that's 17ft) long and shaped to hit 250mph. It stands out. There are a number of design influences at work on it - some legacy, some new, some sublime, some not - although quite obviously it is the flow of the air around, over and under the body which has been its guiding principle. In terms of drag efficiency, it's the slipperiest McLaren ever - something you can well believe when stood next to it.
There are several other sentences ending in 'McLaren ever' to consider, too. Aside from conceding that it is indeed a rear-drive petrol-electric hybrid, Woking is disinclined at this stage to talk about what exactly it has attached to the existing 4.0-litre V8. But it has gone so far as to reveal that, in total, it outputs 1,050hp - 134hp more than the P1. Despite being substantially longer than its sibling, the Speedtail, for reasons we'll come to in a moment, it is only marginally heavier at 1,430kg (dry) and, in terms of straight-line acceleration, vastly quicker.
To illustrate this, McLaren cherry picked an astounding number: 0-300km/h (or 186mph) in 12.8 seconds. That's almost 4 seconds quicker than a P1 (16.5 seconds). For additional context, in 2011, Autocar needed 16.2 seconds to get a 1,200hp Bugatti Veyron Super Sport to 180mph. And the engineers are only just getting started. That 250mph, you suspect, is probably not the result of actual testing (given the limited number of places in the UK where such a speed could be achieved) but rather a projection of where McLaren comfortably believes it will be.
Certainly there was a tacit admission from those in charge that its quoted V-Max is first and foremost about exceeding the 243mph set by the McLaren F1 rather than chasing an absolute, at-all-costs limit. The Speedtail needs to work as well in a Sainsbury's car park as it does at the end of a runway, was the manufacturer's overriding theme. Be that as it may, the car still comes with a special 'Velocity' mode that lowers it by 35mm and 'optimises the powertrain and aerodynamics'. So it's fair to say it's taking it seriously.
Not that anyone would suggest otherwise in a car that looks custom-built for the business end of the Mulsanne straight. Where to start? That teardrop of a cockpit? It's accessed by powered (a first for McLaren) double-skinned dihedral doors that feature a single piece of 'wrapover' glazing which forms part of the roof when closed. The windscreen sweeps back overhead, too - both feature electrochroamatic technology, which means they forgo the use of sun visors or shades. The wing mirrors? Gone. Replaced by two digital cameras which slide out of the bodywork and project their wide-angle footage onto two dedicated screens inside.
Those wheel covers? Carbon fibre, naturally, and static. McLaren says that owners can remove them if they wish, but it considers them a crucial part of the car's aerodynamic package. And that body? Also carbon fibre, every panel, from front to back and designed with as few shut lines as possible. Not just any old carbon fibre, either; some of it is Titanium Deposition Carbon Fibre, which means that a micron-thin layer of titanium has been fused directly into the weave, thus becoming an integral part of the material and delivering a chrome-effect shimmer. It can be anodised too, meaning you can have any colour - or even images or symbols (the McLaren logo on the rear of the driver's seat is rendered in this way).
If that's not space-age enough for you, McLaren plundered another bright idea straight from NASA itself. Just visible on the car's trailing edge are four innocuous slits, two either side. Those are the (now patented) rear ailerons. Rather than use a conventional mechanism, they use 'flexible' carbon fibre to allow the bodywork to hinge without an additional, air-unsettling gap. In conjunction with the diffuser, they actively adjust to move the centre of pressure, providing the Speedtail with downforce precisely where it is needed.
Under the body is a significantly altered Monocage. The Speedtail is 50mm longer in the wheelbase than a 720S and the bulkheads have been adjusted for the new layout at the front, and to cradle an all-new high density battery at the back. Like the rest of the powertrain, its precise specification remains strictly under wraps, although we learned that it'll use wireless inductive charging rather than a messy plug and that it will not provide the Speedtail with any electric-only range. Expanding on that, Andy Palmer, the Ultimate Series top banana, told PH that McLaren had used hybrid technology 'in a very different way' this time around.
Elsewhere, the car gets the same aluminium hydraulic RaceActive Chassis Control II suspension as the Senna, although with only two modes - Sport and Comfort - available alongside the Velocity setting. The carbon ceramic brakes are from the Senna, too. The interior, though, is not shared - not even a little bit. Building on its 'ultimate road car' theme, McLaren has gone all in with what it describes as 'technical luxury'. Even spoilt members of the automotive press weren't allowed to climb into the captain's chair, but it looks fantastic and the job of scrambling into it has apparently been made easier by a new 'directional' leather finish that lets you glide across the passenger seats.
Like the F1, these are set back and fused directly to the tub. The custom-made driver's seat - which is said to be directly inspired by the one which sits in the Speedtail's spiritual forbear - is flanked by two touchscreens with a digital instrument panel straight ahead. Combined with the fixed displays for the pop-out wing mirrors (a legal requirement) the dash is by far the most advanced of ever featured in a McLaren. To make room for all the screens and to accommodate the centre seat, most of the conventional controls - including the Active Dynamics - have migrated to a panel over the driver's head.
Any surface which isn't LCD or glass or Thin-Ply Technology Carbon Fibre, is covered in aniline leather - which extends all the way into the footwells and even covers the floor. It lines the luggage compartments, as well - of which there are two, providing 162-litres of bag-carrying space (enough, McLaren says, for a couple of bespoke cabin bags). The implied level of practicality - along with the fact that the Speedtail has room for three - is a key aspect of the car's GT status, and will help make it a usable prospect for the 106 people who have already signed up to buy one at £1.75m a pop plus taxes. The manufacturer could have shifted three times that number, of course, but that's the amount of F1s it sold from '93 to '98 - and with its fastest, most ambitious road car ever, it's clearly gunning for a similarly vaunted place in history.