The old adage about building a house on strong foundations rings true with cars, too. There are obvious similarities between the importance of a structurally-sound base for a house and a decent chassis on a road car, but the analogy runs deeper.

If the base model in a range of cars is a bit of a wet fish, no amount of high-tech optional extras and equipment will be able to cover it up. Stripping a model back to its basic set-up is a great way to test its most basic abilities.

This is certainly the case with the Citroen C5. The more stylish new model is intended to make a greater impression on the private buyer, but the fleet market remains one of its most lucrative arenas.

With that in mind, it is worth considering that many of the examples sold will be closer to the bottom end of the trim-level ladder. Should you have a generous company scheme, or a small windfall burning a hole in your pocket, it is reassuring to know that you can splash your cash on all manner of ingenious systems and technologies, but the C5 is one of a handful of cars where little kudos is lost in opting for the base specification model.

That is chiefly because, in entry-level SX form, the C5 retains the same sharp looks and individual styling as the rest of the range. Even with steel wheels — usually the first standard piece of kit to be shed to increase a vehicle’s standing in the pecking order — the C5 looks as upmarket as any of its rivals.

Executive wheel trims are not the only area where Citroen has succeeded in keeping costs down, without sacrificing quality.

Famed for their uncannily absorbent ride qualities, Citroen has usually opted for hydro-pneumatic suspension systems. The French manufacturers Hydractive 3 Plus self-levelling system is present elsewhere in the range, but the base diesel version makes use of a more traditional coil spring arrangement.

Drivers need not feel short-changed, however. The ride quality is everything you might expect from a medium-to-large Citroen model. It wafts over rough surfaces transmitting little into the cabin, yet still feels firm under sharp cornering. Comfortable and confidence-inspiring, the chassis is a big success.

That is not to say the model is particularly sporty. In 1.6-litre diesel mode, the emphasis is firmly on economy and comfort for the high mileage driver. There is little escaping the fact that it is a small engine for a reasonably large vehicle and that is highlighted in the zero to 62mph times.

However, the C5 is such a relaxing and refined car to drive that a lack of outright performance never really enters the equation.

The model is perfectly suited to long distance driving with steady, linear performance from the diesel engine, and a long top gear on the five-speed manual box performing like an old fashioned overdrive; dropping the revs down to a steady hum on the motorway and ensuring the engine sips fuel.

Impressive real world economy and emissions that cut company car drivers and fleet managers a big break are the result.

Impressive levels of interior refinement combine with the excellent ride to render the longest journeys powerless to take their toll on the driver. The comfort factor is again underlined with standard cruise control, automatic air conditioning and a speed-sensitive sound system.

Citroen has made a concerted effort to increase interior quality in this important sector, too. The C5 is a noticeably classier affair with material that, although not as refined as those in the established premium models, are of improved quality compared with Citroens of old.

Key to the more upmarket feel inside is the floating steering wheel design. With many of the driving-related controls located within the large hub of the steering wheel, the rest of the dash is largely free of clutter.

This is a particular bonus for the higher specification models, allowing the additional equipment to slot in without over-complicating the centre console, and in the SX it also creates a less fussy interior.

The steering itself is speed-sensitive, but hovers on the light side anyway, in keeping with the model’s comfort philosophy.

Elsewhere, the digital instrument cluster is a real gem — easy on the eye, yet extremely clear. The large centre console impacts a little on driver leg room, but the highly-adjustable driving position means it is easy to get comfortable.

In the rear, leg room is ample, but taller passengers might find the sloping roofline infringes on head room.

An entry-level model to be proud of, Citroen’s C5 SX lays some very strong foundations for the rest of the range.

Model: Citroen C5 1.6HDi SX Performance: 0-62mph 13.4 seconds, top speed 119mph Economy: 50.4mpg (combined) CO2 emissions: 149g/km Price: £17,595

Web: www.citroen.co.uk