A lengthy motorway journey followed by a close encounter with some twisty, undulating B-roads, it was a trip with all the ingredients to provide an accurate impression of an executive saloon's true abilities. The Peak District was the destination and Audi's latest A6 3.0-litre TDI diesel was the car.

The general consensus of opinion pre-trip was that the big black Audi would devour the motorway mileage with a flourish and barely a flicker of its fuel gauge. The Peak District's serpentine back roads, it was thought, would present more of a test for such a big smoothy. In the end, that's just about how things panned out but there were more than a few surprises along the way.

Like most cars of its ilk, the Audi A6 is well equipped to soften the hard edges of long distance motorway travel. Leather, wood, chrome, the interior is typical Audi with expanses of the marque's favoured materials apparent at every turn. Even where plastics are employed they are plastics cunningly doctored to give the effect of leather, wood or chrome. The result is a relaxed, quality, drawing room ambience - a cocoon of tranquillity for the bothered executive and an ideal environment in which to undertake a trip of a few hundred miles or more. Two-zone climate control prevents cross-cabin arguments about who's too hot and who is not. Meanwhile, the superb Audi Concert sound system provides the entertainment and the satellite navigation system deals a terminal blow to the tired old road atlas. Actually, we took the tired old road atlas anyway - past experiences have taught that a healthy mistrust of satellite navigation is often, well, healthy.

Just 50 miles in and it was apparent that motorway cruising is a walk in the park for the A6. Concerns that the car was prone to horrendous wind noise proved unfounded once we realised that the sunroof was very slightly open and the suspension was obliterating the carriageway expansion joints to impressive effect. Even at cruising speed, a prod of the throttle rapidly puts on the 10mph you need to bypass a pair of overtaking HGVs and when it's time to rest those feet, a spell of cruise control works wonders. The torque emanating from the 225bhp 3.0-litre turbo diesel engine, means accelerating back up to speed out of heavy traffic is a breeze and even if you drop down to speeds of 40mph, the Audi will still pick up in sixth gear.

The wonderfully smooth and lorry-free M6 toll road threw the satellite navigation system something of a curve ball. The on screen map showed us, clear as day, ploughing across open fields and farmland with no road in sight. The audio instructions calmly requested all kinds of illegal manoeuvres every time our cross-country course intersected a local B-road that did appear on the map. An updated mapping CD in the boot-mounted drive would have solved the problem but so did the deactivation of the system's voice commands and on rejoining the M6 proper it soon regained its bearings.

"On our trip, the car went the whole way (nearly 500 miles) on a single tank."

The roads around the village of Warslow in the Staffordshire Peak District could have been created expressly to upset the equilibrium of a large executive saloon. Winding across the landscape connecting clusters of small stone houses, the narrow tracks twist up inclines and plunge into shallow valleys. These roads would ask big questions of a well-balanced roadster - an observation conformed when a convoy of day-glow Vauxhall VX220s, complete with grinning drivers, blasted past in the other direction. The Audi fared better than many people would imagine here. The suspension still soaks up the undulations and ruts to a great extent, which can be a little disconcerting, but when you ask it to brake in a hurry or turn sharply around a dry stone walled hairpin, it does so with reassuring agility.

Performance-wise, the 3.0-litre engine is a real pleasure to punt around. It's smooth and quiet but when you stir it up there's genuine bite to the acceleration. 0-60mph in 7.1 seconds is the official performance figure but powering out of a corner up a Peak District hillside, the flexibility of the powerplant makes it feel considerably quicker than that.

The A6's handling on some taxing but enjoyable roads felt very secure, which is more than can be said for yours truly during a night at Warslow's Greyhound Inn. The 17th century pub was brimming with character and hospitality but the landlord's spirited rendition of the ghost story attached to the building did little to facilitate a good night's sleep. Still, £35 a night for a well-appointed double room and breakfast seemed excellent value.

The next morning it was a short drive through rolling hills bordered by streams and criss-crossed by the dry stone walls to a destination that would put the A6's high speed manoeuvrability firmly in perspective - Alton Towers. With names like Nemisis, Submission and (I can hardly bring myself to type it) Oblivion, the rides at this theme park lead you to suspect that you're in for something mildly unpleasant but the reality made the Greyhound ghost story seem like an episode of The Tweenies. When you've had your sense of direction turned inside out by the dizzying Spinball Wizzer, been fired headfirst through the woods by Air and endured a 50ft vertical drop into a misty pit on Oblivion, the A6's cosseting interior was a joy to collapse into for the drive home.

The trip proved that the big Audi is more than a long distance cruiser. It's actually very capable in the twisty stuff for a car of its considerable size. The gearbox was smooth on the motorways legs but also outstanding for powering up the Peak District's many inclines, traction was near faultless and the chassis remained poised on some testing thoroughfares. A6 buyers will be pleased to know that their cat can cut it cross-country but there's no doubt that the motorways and A-roads are its preferred habitat. Effortless performance, well-crafted interiors and a quality ride all help here but the biggest draw of all for Audi A6 diesel customers will be the fuel economy. On our trip, the car went the whole way (nearly 500 miles) on a single tank. That's better than 33mpg and that's very impressive for a big executive saloon being driven reasonably hard.

Travel story- FACTS AT A GLANCE

CAR: Audi A6 3.0TDi

PRICE: £31,045 - £34,885 - on the road

INSURANCE GROUP: 16

CO2 EMISSIONS: 229g/km

PERFORMANCE: Max Speed 151mph/ 0-60mph 7.3s

FUEL CONSUMPTION: (combined) 34.0mpg

STANDARD SAFETY FEATURES: Twin front, rear & side airbags, ABS, ESP, EBD

WILL IT FIT IN YOUR GARAGE?: Length/Width/Height(mm)4916/1860/1460

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May 19th 2005