The powertrain line-up is extensive and ranges from a pair of three-cylinder turbocharged 1.2-litre Puretech petrols of 109bhp and 128bhp to diesels of 1.6 and 2.0-litres that run from 91bhp to 178bhp. These are BlueHDi engines, which feature an advanced exhaust cleansing system that uses an Adblue additive in combination with a diesel particulate filter to further reduce NoX emissions and capture 99.9 per cent of particulates.
Like the 308 hatch, this is a car that’s up to 140kg lighter than its predecessor – a lightweight thermoplastic tailgate is a feature of the SW – and it also benefits from a centre of gravity that’s 20mm lower than before thanks to the relocation of the drivetrains and a lower roof.
You can fractionally undo that advantage by specifying an impressively large panoramic glass sunroof, incidentally.
That aside, the combination of lower weight and more economical engines allows the 1.6-litre BlueHDi 120 to achieve a combined 91.1mpg and emissions of 85g/km – the lowest in the segment, although you’re unlikely to see 90mpg in reality of course. It’s the more powerful diesel that we sample here, however, the 148bhp 2.0-litre BlueHDi achieving a still-impressive 70.6mpg and emissions of 105g/km with a six-speed manual transmission.
When the optional panoramic sunroof is fitted, this is a car that feels almost spectacularly airy, especially if you sit in the rear. It feels bigger still if you fell the rear seats, the load bay doing a good job of emulating a van.
The extra length in the floor is good news for back-benchers, who will enjoy more kneeroom than they would in the slightly confined hatchback and a loftier seating position than they’ll experience in a Ford Focus or Volkswagen Golf estate, which is good news for kids craning for a view.
Peugeot’s new turbocharged 1.2-litre three-cylinder engine is offered in two guises - 109bhp or 128bhp versions. Like Ford’s smaller EcoBoost unit, the latter variant is a fine advertisement for downsizing - being smooth and torquey enough to pull a 25mph/1000rpm sixth gear with ease and suffering almost no turbo lag. It also emits 114g/km of CO2 in this SW.
In higher-spec 308s, a Sport button sharpens the throttle and firms the steering. With the triple, it also adds a layer of noise to the deep, distinctive three-cylinder thrum – a discordant gruffness that ruins the soundtrack completely. It’s a daft addition and should be deleted forthwith.
The 2.0-litre turbodiesel is good for a stout 148bhp and 277lb ft of torque, although its arrival at a slightly higher than average 2000rpm is betrayed by a standing start take-off that’s a little less effortless than you might expect.
However, committed sinkings of the accelerator soon produce pleasingly brisk progress, and the thought that this Peugeot’s performance will be no embarrassment when fully laden. It’s at its best at speed, in fact, when its effortless demeanour is likely to make light work of family missions to a distant holiday destination. There is a 178bhp diesel which provides more than brisk progress when pushed and is the reserve of the range-topping GT trim.
Speed also smoothes out a ride that occasionally feels a little lumpy over broken surfaces and quietens an engine that, while never vocal, is not quite as subdued as the best 2.0-litre oil-burners out there. That said, the general refinement of this car is pretty good, as is comfort.
Its most striking feature remains the small, low-set steering wheel and the instrument binnacle that levitates above it, this layout more successful here than the same arrangement is in the Peugeot 208.
The small wheel heightens the car’s wieldiness to an extent that is possibly too much at times, when modest inputs produce a greater directional effect than they would in a bigger-wheeled car. But you soon acclimatise, to enjoy handling that’s tidy and capable if a fraction less crisp than that of a Focus.
The 308’s cockpit is also notable for a 9.7in screen that significantly reduces the cabin’s button count, perhaps by too much in the case of the climate control, which requires fiddly extra steps to achieve a mere tweaking of air temperature or direction.
On the equipment front, there are five trims to choose from, with the entry-level Access models coming as standard with 15in steel wheels, air conditioning, DAB radio, Bluetooth and USB connectivity, and cruise control. Pay a little more gets you 16in alloy wheels, automatic lights and wipers, rear parking sensors, dual-zone climate zone and Peugeot's 9.7in touchscreen infotainment system complete with sat nav, while upgrading to Allure adds 17in alloy wheels, front foglights, aluminium roof rails, LED headlights, folding door mirrors and front parking sensors.
The range-topping GT trims add numerous luxuries, with the GT-Line equipping the 308 SW with 18in alloys wheels, privacy glass, LED foglights and a reversing camera, while the GT model gains a beefy bodykit, lowered ride height, adaptive cruise control, Peugeot's emergency collision alert and autonomous braking system, and keyless entry and start.
Ultimately, if absolute space is your goal then you should consider the Skoda Octavia, which not only swallows a bigger load but also provides more rear-seat legroom.
The Peugeot 308 SW nevertheless has strong appeals of its own, including an attractively designed interior, a clean, unfussy exterior and good all-round refinement. And the on-paper promise of economy is certainly there, together with performance strong enough to deal with all loads when you opt for the 2.0-litre diesel. Even equipped with the 127bhp 1.2-litre three-pot turbo, it's a decent proposition.
We’d recommend the panoramic roof for its ambience-transforming effects, and, although it’s a long way from turning this car into a GT estate, the driver’s sport pack, which alters the powertrain mapping and steering feel, triggers a digital engine sound-enhancer, turns the instruments red and provides additional dynamic data, is worth having for the modest £375 it costs.