Jaguar XJ TDVi Executive

Jaguar has filled a huge gap in its range with this car - and rivals should be worried. The XJ diesel's mix of price, performance and economy, plus tax-friendly emissions and low servicing costs, will find appeal with private and company buyers. But best of all, refinement is class-leading. We wonder why anyone would go for the 3.0 petrol version.

While the 155bhp X-Type diesel adds extra appeal to Jaguar's small car range, the new XJ is arguably one of the most important models the firm will launch this year.

The luxury saloon class's new-found love of diesel has left Jaguar trailing. With more than 50 per cent of buyers favouring oil-burners, the long awaited XJ TDVi is charged with helping the Big Cat claw back much lost ground.

Priced £43,995 in Executive trim, the newcomer undercuts Audi, BMW and Mercedes rivals by as much as £7,000 - but can it uphold Jaguar's reputation for performance and refinement?

Powered by the same 2.7-litre twin-turbocharged diesel as the S-Type, the TDVi delivers 206bhp and 435Nm of torque. In the lightweight aluminium XJ, that's enough for 0-60mph in 7.8 seconds and a 141mph top speed.

But more impressive is its response on the move. Mated to a smooth six-speed automatic gearbox, the unit provides strong and effortless acceleration, making overtaking simple. And while the XJ TDVi is 120kg heavier than a 3.0-litre petrol model, the standard-fit air-suspension means it rides just as comfortably and handles as sharply.

Refinement is first-class, too. Air-tight seals between the bonnet and engine bay, along with new laminated glass, ensure noise is kept to a minimum at speed. Yet the car is also impeccably quiet when stationary, thanks to clever engine mounts which dampen 90 per cent of the normal vibration at idle.

The XJ TDVi makes a strong case for itself as a business proposition. Combined economy of 35mpg, 214g/km CO2 emissions and a 29 per cent company car tax band all beat the Audi A8 3.0 TDI and BMW 730d - and are on a par with Mercedes' S320 CDI. But thanks to longer service intervals than petrol XJs, Jaguar is confident of savings on maintenance costs as well.

The engine is not the only change - the diesel brings styling tweaks for the entire range, although they only involve the removal of body side mouldings. Designers have left the interior alone.

Uprated brakes also improve stopping power, but it was the engine range that required attention - and this diesel brings it up-to-date. The XJ TDVi is a fast, refined and cost-effective package.