The Peugeot 3008 HYbrid4 is the world's first diesel-electric hybrid, and it offers four-wheel drive capability in a vehicle that emits just 99 g/km CO2 and returns 74 mpg.

So far, we've had lots of petrol-electric hybrids, such as the Toyota Prius. The idea behind the Peugeot 3008 HYbrid4 is that, as a diesel engine is 30 per cent more economical than a petrol unit, a diesel-electric hybrid will be more economical than a petrol-electric hybrid.

In particular, a diesel-electric hybrid will be more economical over long distances, when running mainly on its diesel engine. However the 3008 HYbrid4 also offers good economy in urban areas, when it can operate in zero-emissions mode - ie. when the car runs solely on its Nickel Metal Hydride batteries and electric motor, and doesn't need its diesel engine at all. The car can sustain such zero-emission running for over two miles before the diesel engine has to kick in. Once that happens, the hybrid battery can be recharged and it can once again operate in zero-emission mode.

Peugeot claims that the 3008 HYbrid4 will operate in zero emissions mode for around two-thirds of city driving, and perhaps more interestingly, that it will still operate in zero emission mode for one-third of the time when driving out of the city. This could equate to 174 miles out of the car's total range of 558 miles being completed in ZE mode.

The resulting official emissions are 99 g/km CO2. This is a highly impressive figure for a relatively large crossover, and one that also has four-wheel drive capability. The 3008's diesel engine powers the front wheels, and the electric motor powers the rear wheels. The diesel engine and the electric motor both work together to provide four-wheel drive, when up to 40 per cent of the torque can be sent to the rear axle.

This situation occurs when the hybrid battery has sufficient charge; but even if the battery runs out of charge, despite there being no mechanical connection between the front and rear axles, the rear wheels can instead be powered from the diesel engine's alternator. So theoretically the 3008 HYbrid4 should be able to drive all day in four-wheel drive mode - although there is less torque sent to the rear axle when running from the 8 kW alternator, so the four-wheel drive capability is reduced. Although there's no time limit to the use of the 4WD system, it can only be used up to 75 mph.

In total, the car has four drive modes: Auto, Sport, ZEV and 4WD. Auto is recommended for the best economy in most situations, with the car deciding for itself when it should be in diesel, electric, or diesel-electric mode.

Sport allows the car to change gear more quickly and to hold on to each gear longer. If extra power is required, the diesel engine and the electric motor can work together - providing four-wheel drive.

ZEV keeps the car in electric-only mode - while the battery charge can sustain this. If you need extra response, then the diesel engine can cut in.

And 4WD ensures both the front and rear wheels power the car, so providing extra traction in conditions such as sand, mud or snow.

Most current petrol-electric hybrids have Continuously Variable Transmission (CVT). This means that if you accelerate enthusiastically, the engine revs rise, but you don't make any directly-related forward progress, and this sensation is not to everyone's tastes.

In the interests of efficiency, the 3008 HYbrid4 is fitted with Peugeot's electronically-controlled 6-speed manual (EGC), or 'automated manual', gearbox. This is similar to automatic transmission in the sense that you can keep it in Drive and the car changes gear without the driver needing to use a clutch. But it's like a manual in the way that the gearbox still changes gear with a pause between gears.

Like a CVT, this is also not to everyone's tastes, as it can feel slow to change gear, with a noticeable pause in between gears. You can override the automatic change by using the paddle shifters behind the steering wheel, which can help things, but that somewhat defeats the object of having an automatic function.

Anyway, the good news is that in the 3008 HYbrid4, when the diesel engine loses its drive during the gear change, the electric motor 'fills the gap' and provides power, and this does improve the operation of the automated manual box.

So how does the 3008 HYbrid4 drive?

Well, there's more good news - it drives very much like a normal diesel 3008. This should reassure people who are concerned that the 3008 HYbrid4 may be some form of new-fangled technology that they should be wary of (apart from a few extra badges, there's also very little to differentiate the exterior of the car as being different to the standard 3008).

Of course, when you start the car, it's likely that it won't make any noise, as it's probably running on electric power only. You can then pull away and drive between two and three miles at city speeds purely on electric power. This means that the car remains silent, yet it has impressive levels of torque and acceleration. We've driven pretty much every hybrid and electric car that exists, but it still feels strange - yet refreshing - driving an electric 3008. In order to optimise the car's range, the effectiveness of the air conditioning is reduced when running in in electric mode.

Once the range of the hybrid's battery has expired, the car switches seamlessly to diesel power. You'd imagine that you would notice the switchover more with a diesel engine than with a petrol engine, as diesels are generally noisier, but under most driving conditions you're not aware of the changeover. Under hard acceleration you can hear and feel the diesel kicking in, and this is also when you'll catch out the gearbox. Generally, it seems that Peugeot's engineers have genuinely fixed the pause during gear changes by using the electric motors to fill the gap, and the driving experience is definitely smoother than the non-hybrid version of the 3008 as a result. However if you drive progressively in Sport mode, you'll find that the gearbox isn't as smooth, the revs can rise, and the engine sounds noisy.

The 3008 HYbrid4 has a 2-litre diesel engine, which develops 163 bhp. The electric motor develops peak power of 37 bhp. This gives a total of 200 bhp. In terms of torque, there's 300 Nm from the diesel engine and a peak of 200 Nm from the electric motor. This gives good rather than blistering performance on the road, but these are decent power and torque figures, especially when looked at in combination with 99 g/km CO2 emissions and 74 mpg.

As you decelerate and brake, the car recovers the energy that would otherwise be lost, and uses it to recharge the battery. When you come to a standstill, thanks to the Stop & Start system, the diesel engine cuts out, and this certainly helps with the car's low emission figure. It also makes it much kinder in terms of local air quality, however diesels do emit higher levels of particulate and NOx emissions than petrol. Peugeot has its FAP Diesel Particulate Filter technology which is designed to cut down such emissions. However diesels can have problems with the DPF becoming clogged up if used exclusively on short start-stop city journeys, so this car is better for longer journeys combined with occasional city use.