Is a 2.0-litre engine really up to the job of powering a fully laden estate car? The question is particularly apt in relation to Citroen's C5, a model fast finding favour with fleets because it boasts the largest load capacity in its class.

At first sight, it's tempting to suspect that a motor sized at anything less than 2.2 litres would struggle to cope should users decide to make the most of this car's internal volume potential, which stretches to a massive 1,658 litres.

But that is not the case, as we've just discovered after putting the 2.0-litre powered C5 hold-all to an unusually arduous task. It fell to the lot of the Citroen to carry a large amount of gear to a destination more than 1,000 miles away in France, and we wondered if the fact that the journey had to be made in one day would prove too much for the car's relatively modest engine.

But we need not have been concerned. Any doubts about the capabilities of the HDi turbodiesel were soon dispelled: despite the load, it pulled strongly from rest, was a stout performer mid-range and proved to have sufficient reserves of power for progress to be maintained on long inclines.

For all that, the refinement of the unit during our mile-munching exercise over the French motorway network was even more impressive.

Even though the rev counter needle rarely went beyond the 3,000rpm mark, the high-geared HDi never felt stressed and cruised effortlessly at the legal limit. As a result, the 2,100-mile round trip was completed at an average speed of 72mph with overall economy of 42.2mpg - not bad for a load lugger and proof that the latest diesels offer a tremendous combination of stamina, good driving characteristics and low operating costs.

After six months, we've found our SX version to be a sound fleet choice - cost- effective and well-equipped for family and business use.

The car's interior packaging has proved extremely versatile and we've found the supple Hydractive 3 suspension system to be beneficial in serious long-distance use. As our long-haul exercise showed, the system cossets both occupants and load with a ride quality that helps drivers shrug off the effects of long hours at the wheel.