The design of Jaguar XF has evolved but its technology and breadth of performance are revolutionary. Designers Ian Callum and Adam Hatton explain how Jaguar’s heartland saloon has grown up

As you walk up to your Jaguar XF from the rear, your hand rising and reaching for the driver’s door handle, you might recognise in the radius at the end of the bonnet the ghost of the very first sports saloon, Jaguar’s Mk II from the 1960s. For anyone who knows that icon, seeing this familiar curve in a car as modern as XF is uncanny. This is an utterly modern design, a car whose physical form, like the performance and technology it packages, looks to the future.

>But the skill of Jaguar’s director of design Ian Callum and his team is such that they can incorporate these subtle references without compromising XF’s modernity. They’re having fun. And they have created a car that, like all good design, looks great now, but will continue to reveal more details like this, the longer you live with it.

The original Jaguar XF had already become one of those iconic Jaguars. ‘So we decided quite consciously to evolve it,’ begins Callum. ‘The first XF transformed the brand and got this modern design language across,’ says Adam Hatton, tasked by Callum with overseeing the XF’s exterior. He also worked on the first one. ‘I think the mark of good car design is that when you’re replacing it, it still looks good on the road and sells well. So this isn’t the time to revolutionise XF. Rather, we wanted to build on everything that’s great about it.’

Of course, since that first XF appeared in 2007, much has changed. The more compact, sporting XE saloon launched, allowing the bigger XF to mature slightly. And Jaguar’s huge investment in technology has brought lightweight aluminium intensive architecture, the advanced four-cylinder Ingenium engines made by Jaguar in its engine plant, and a series of driver-focused technologies, from the class-leading InControl Touch Pro infotainment system, that enables much greater levels of connectivity, to All Surface Progress Control, which allows drivers to pull away at low speed with confidence in slippery conditions (the XF was the first in its segment to offer this).

You can see the technical advances that XF makes in its forms and proportions. The intelligent aluminium intensive architecture that underpins it is exactly that: an architecture, not a fixed ‘platform’ over which a body must be stretched. So the design team was free to start from the correct first principles, positioning the wheels exactly where they wanted them for perfect proportions and stance.

Although this car is actually slightly shorter than the outgoing XF for improved city manoeuvrability, it looks like a bigger, more serious car because the wheelbase has been lengthened and the wheels pushed out to the corners. A shorter nose balances the more formal, upright grille to maintain the car’s dynamism, while the elongated section between the front axle line and the steering wheel lends the car an even more premium feel, emphasising the proportions you expect of a luxury saloon with a big engine and rear-wheel drive, (even though you can have your XF with a four-cylinder engine and all-wheel drive too).

‘We repositioned XF slightly because we have XE in the portfolio,’ says Hatton. ‘The outgoing XF had to do everything. It was the entry car, the business car, the four-door coupe. Having XE really allowed XF to develop into what you see here.’

Of course, more length between the axles creates more space in the cabin, and XF will have the best rear legroom in its class. So the design team chose to communicate this with a ‘sixth light’, an additional window set into the C-pillar behind the rear doors. This, and the slightly more pronounced, formal ‘deck’ over the boot are probably the most striking changes to XF.

But it’s only when you speak to the designers that the subtleties of their work become apparent: the way they capture, control and direct light to bring a shape to life, and make us fall in love with a design without entirely knowing why. Look for the gentle ‘fluting’ that runs back into XF’s bonnet from the headlamps – a hallmark of Jaguar saloons of the past – but also a way to capture arrowheads of light on the bonnet to catch your eye. Or best of all perhaps the ‘spear of light’: the line that flows back from around the front wheel arches and along the body side, emphasising the more level waistline of this more formal saloon.

‘The Mark II had this lovely line coming over the front wheel, and going all the way to the rear,’ says Hatton. ‘We’re just reinterpreting that in a very modern way. Ian christened it the spear of light. You can see how that curve is absolutely perfect. It tapers off really nicely to the rear. It gives that very elegant Britishness to the car. It also slims the car down even further. XF is lightweight, and our job is to show that in the design of the exterior.’

Callum and his team have married perfect stance and proportion with clever, subtle detailing. XF again displays Callum’s insistence on a design with a voluptuous view from directly above, which in turn causes your perception of the car’s form to shift as you move around it at street level. But design doesn’t exist in a vacuum. Just as XF’s design has been helped by its aluminium intensive architecture, so the design team helped Jaguar’s engineers and aerodynamicists to create – jointly with XE – the most aerodynamic Jaguar ever with a drag coefficient of just 0.26.

Combine that slippery shape with the highly-efficient Ingenium four-cylinder diesel engine, a weight saving of around 190kg, and further fuel-saving advances like the electric power steering, and you will be able to specify an XF that will emit as little as 104g of CO2 for every kilometre travelled*.

‘That’s a big story with XF,’ says Callum. ‘We worked with the aero guys right from the first sketch. If you do it holistically, and just try to make the whole car as aerodynamic as possible, you end up with something amorphous. Instead, we work the details, managing the airflow through the car and around the car, like a racecar engineer would. That way you get a much better result, both for design and efficiency.’

They both know they’ve got that perfect result: a car that unites Jaguar’s now-expected design leadership with state-of-the-art technology and an extraordinary breadth of performance. Hatton says, ‘You know, it’s not so easy to create a car that doesn’t have an unflattering angle. But I’m convinced that you couldn’t take a bad photograph of XF.’

*The fuel consumption figures provided are as a result of official manufacturer's tests in accordance with EU legislation.

A vehicle’s actual fuel consumption may differ from that achieved in such tests and these figures are for comparative purposes only.

Official fuel consumption figures for the XF in l/100km (mpg): Urban 11.9 (23.7) – 4.8 (58.9) , Extra urban 6.7 (42.2) – 3.6 (78.5) , Combined 8.6 (32.9) – 4.0 (70.6) . CO2 emissions g/km: 204 – 104.