BMW had a go at introducing a 7 Series Hybrid a few years ago, based on the 4.4-litre V8 from the 750i. It was a technological first for the carmaker, and very powerful too. But with 219g/km CO2 emissions and only 29.1mpg on offer it didn’t make much sense in Europe. The first ActiveHybrid 7 was only sold in North America.

This time, the package is a little more usable. The V8 engine has made way for the same six-cylinder, twin-turbocharged engine found in the ActiveHybrid 3 and ActiveHybrid 5, and fuel efficiency has improved dramatically as a result. The new car returns 41.5mpg on the combined cycle and emits 158g/km CO2, while offering a 12bhp improvement to reach 354bhp.

But sales projections are still modest. The UK-favourite 730d, which has also improved over its predecessor, is expected to make up the bulk of sales here. BMW expects the ActiveHybrid 7 to account for less than 2% of UK sales, or around 20 vehicles per year.

Of course, the 730d will make more sense for most fleets. It’s cheaper at the front end, which leaves more room for luxurious toys, still offers ample power and it’s more efficient and lower in CO2 emissions than the hybrid.

That’s only half the story though. Put the ActiveHybrid 7 into its ECO PRO driving mode, and wherever possible it’ll switch off and decouple the petrol engine altogether. The diesel may have the edge on fuel economy, but it can’t cruise silently through town centres and coast down the motorways like the hybrid. That’s a characteristic which really suits a luxury car like this, and which benefits fuel efficiency.

Nor can it offer the same split personality. Push the drive selector into Sport mode and the ActiveHybrid 7 uses the electric motor to boost the petrol engine, while the throttle sharpens up considerably. Even partially depressing the right hand pedal makes the 7 Series respond with a surge of forward motion the diesel just can’t muster.

But the automotive world is full of tall promises, and it’s easy to be sceptical about ambitious fuel efficiency figures. These seem to come close, though. On test, the ActiveHybrid7 managed almost 34mpg on a combined route of motorways, A roads and town centres, all without holding back too much on the throttle. Drivers spending most of their time in city centres will reap the biggest rewards.

Rivals are few and far between, comprising only the Lexus LS 600h which still emits 199g/km CO2. Mercedes-Benz is developing a modular hybrid system for the next S-Class, Audi is working on an A8 hybrid and Jaguar has been very public about its ambitions for a plug-in hybrid XJ, but so far none have materialised which gives the ActiveHybrid 7 a free run of the market for those wanting a powerful sub-160g/km limousine.

The range is identical to the conventional 7 Series, which means a choice of standard and M Sport trim levels and long or short wheelbase bodyshells. Like the rest of the range, it’s a firmer-riding car than the sector’s biggest seller, the S-Class, and a little more understated than the Jaguar XJ’s wow-factor interior and exterior styling. All you really lose over the other models is boot space, which is almost halved to make room for the battery.

So while it’s not the first in its class and it won’t be a common sight in the UK, the ActiveHybrid 7 takes electrification into a sectpr that it really suits. It’s more refined, more powerful and is likely to be close in fuel efficiency to the diesel, which mean early adopters are in for a real treat.

Verdict:

A niche car which offers an interesting view of future luxury models, the ActiveHybrid 7 may not make as much financial sense as the 730d but in some ways it’s actually a far more luxurious way to get around. Expect most early cars to be found within the M25, though.

Spec:

Segment: Luxury

Type: Petrol-electric hybrid

Price: £66,040-£71,315  

Fuel: 41.5mpg

Electric range: 2.4 miles

CO2 emissions (tailpipe): 158g/km

Charging port: N/A