Alongside its exciting new fully electric 208 and 2008 models, Peugeot is giving some of its existing range a boost with plug-in hybrid variants of the 3008 and 508.

With benefits aimed squarely at fleet customers, the low-emission, low-tax, high-performing models join an ever-expanding crop of partially electric models in the heartland of the user-chooser market.

The 508, already a favourite of Fleet News – having been Highly Commended in our Best Upper Medium Car category at the Fleet News Awards - receives a new petrol electric powertrain in hybrid guise with CO2 emissions of just 38g/km.

By fusing the existing 1.6-litre turbocharged petrol engine with a gearbox-mounted electric motor, the front-wheel drive 508 hybrid serves up 225PS – the same as the range-topping petrol GT.

The hybrid’s electric-only range is rated at 33-39 miles under WLTP, giving drivers adequate range for short-to-medium journeys.

Our test route saw the battery charge deplete at a rate that makes that range believable – around 34 miles. During longer trips and at higher speeds, the petrol engine jumps into life to minimise the load on the battery.

Like all petrol plug-in hybrids, the zero-charge fuel consumption is likely to be pretty poor. The non-hybrid version (with essentially the same petrol engine) has a WLTP fuel consumption figure of around 38mpg. Once you factor in the hybrid’s 280Kg weight penalty, it’s likely the car will exhibit a bit of a thirst.

While we are talking about that extra bulk, the 508’s finesse in the bends has been somewhat diminished as a result. The lighter BlueHDI versions are more engaging and probably more efficient in the real world.

Performance is on par with rival cars like the Passat GTE, with a sub-eight-second 0-60mph time. But the 508 hybrid doesn’t feel particularly sprightly. The EAT8 gearbox takes a while to wake up and deliver the combined force of the engine and electric motor.

With its relatively small capacity, the petrol engine feels a tad strained too. Those used to a diesel may find the setup a little lacklustre.

When cruising, the 508 is much more at home. Its interior is like no other on the market and refinement and comfort levels are high.

The infotainment set-up leaves a little to be desired, but Peugeot has ticked all the boxes by providing Apple Carplay, Android Auto and a suite of connected services that include app-based interactivity.

Drivers can spec the hybrid powertrain on Allure, GT Line and GT versions of the 508. It is also available on the svelte – and more practical – Sport Wagon.

Peugeot has managed to engineer the battery pack into the chassis in such a way that there is no impact on boot space or rear passenger space.

Prices start at around £35,000 for the Allure, which comes with all the equipment fleet users should need. GT Line versions are more desirable with a sportier edge, while range-topping GT (north of £40k) comes fully loaded.