Jaguar has ambitious plans for the XF 2.2-litre diesel. The new engine, which coincides with a model refresh, is expected to almost double annual sales from 10,400 last year to 20,000 this year, accounting for more than 40% of the total.

With emissions dipping comfortably under 160g/km – at 149g/km it is the lowest CO2 emitting Jaguar ever, equalling the figure set by the 2.0-litre X-Type a few years ago – this engine will boost the XF’s appeal with fleets. Corporate buyers already account for 45% of registrations; the share next year is likely to rise above 50%.

Our model is the £37,765 (P11D) Premium Luxury – one down from the range topping Portfolio. It has just over £4,000 worth of optional extras, taking the P11D to £41,790.

These include a pedestrian-baiting 600W upgrade to the standard car’s 600W B&W sound system (price: £1,350) and a rather more pragmatic cruise control with intelligent emergency brake (£1,275) and blind spot monitor (£460).

It’s worth noting that order books have just opened for a £30,800 fleet-specific SE Business model, which adds Bluetooth and sat-nav over the entry-level SE.

The XF becomes one of the few cars on our long-term fleet not to have winter tyres fitted.

However, Jaguar has put a pack of snow socks in the boot – presumably a cheaper option for the press fleet. Given that both snow and cold weather have been in short supply this winter, it shouldn’t prove to be a concern.

Initial impressions of the 2.2-litre four-cylinder diesel engine are favourable. There’s a bit of clatter when starting up on cold mornings, but this quickly disappears. This is a very refined engine, well suited to its eight-speed auto box; at motorway speeds it’s barely audible. With ample torque at 2,000rpm, the XF is very responsive.

The 149g/km CO2 emissions translates as 52.3mpg on the combined cycle. This could be tricky to achieve. Initially the car settled into the mid-40s thanks to a few motorway journeys, still 14% below the official figure.

However, my daily 17-mile commute to/from work – part stop/start A-roads, part dual carriageway – has seen the fuel efficiency slump alarmingly to 38mpg. That’s a deficit of 27%, and not that much higher than the 35mpg we achieved in the 3.0-litre diesel tested in 2010 (official figure: 42mpg).

Hopefully a few longer drives will help to bring the figure back up – but you’ll have to wait for the next review to find out.