Land Rover, which concentrates on making 4x4 vehicles, is now the star performer in the Ford collective' of car brands.

In 2005 it set a new global record for annual sales with an increase of 14 per cent to 185, 120 vehicles, with USA sales growing by 30 per cent.

The introduction of the Range Rover Sport and the on-going demand for the premium Range Rover has much to do with their success, but it is the Land Rover Discovery 3 that remains the mainstay of their worldwide popularity, with 60,000 sales worldwide last year.

In 2005 What Car? raised a few eyebrows in the industry by making the new Land Rover Discovery 3 their Car of the Year at a time when 4x4s were getting a bad press from the environmental and road users groups.

The Land Rover Discovery 3 was still a winner in 2006, not of the overall title this year but as the Best Large 4x4'. It also won the same category in 2005 on its way to the overall title.

Discovery 3 has two engine options for Europe. A fuel guzzling 4.4-litre V8 petrol unit, and the most popular is a 2.7-litre V6 turbodiesel unit from the Ford PSA (Peugeot Citroen) engine development partnership.

All Discovery models, other than the base TDV6 variant which has five seats, are seven seaters with the rear row folding down into the floor to give a large flat load area still allowing seating for five adults in comfort.

Prices range from £26,995 up to £48,495.The most cost effective model is the TDV6 turbodiesel SE auto priced at £38,490 What Car?'s favoured model. But my test car turned out to be the top of the range diesel version, the HSE, with the standard fit six-speed adaptive automatic transmission priced at a hefty £43,495.

I say hefty', but when you consider the technology this vehicle has, the luxury and all-wheel drive technology it encompasses and the image it presents it is no more expensive than an executive car but it does a lot more.

The Discovery 3 is no longer a bodyshell bolted on top of a Land Rover chassis. It has Land Rover's new Integrated Body-Frame', a system that adopts the torsional rigidity and on-road refinement of a car's monocoque bodyshell with the strength of an in-built chassis frame.

It is still boxy' in shape, but this is a real bonus for interior space. It allows for a relatively high-up command seating position and the stepped roof gives more headroom for second and third row passengers.

Access to all three rows of seats is through the wide-opening side doors. An upper and lower two-piece tailgate allows easy access to the large load area. Both the middle and rear rows of seats fold neatly into the load area floor.

The folding armrest for the front two seats keep the driver and front seat passenger well supported in their seats, off-setting the bodyroll. Needless to say, for this price, the upholstery and door trims are full leather. The heated front seats were a great comfort for my wintry test period.

The interior equipment levels are very comprehensive, everything from automatic front and rear heating, air conditioning through to a navigation and vehicle information system, including visual monitoring of what off-road mode is operating in real-time'.

Another Land Rover pioneering piece of technology is their Terrain Response system; it's a bit like having a driving instructor sat next to you.

This system optimises driveability and comfort, as well as maximising traction from the permanent four wheel drive system which incorporates all manner of on and off-road electronic driving aids, such as hill descent control, four-wheel traction control, two-speed high and low ratio transfer box, front and rear split differentials, lockable centre differential, independent front and rear air suspension, a stability control and bodyroll limiter.

It is a technical masterpiece all operated from a rotary switch and a couple of other switches from the centre consol. The driver can use any one of five automated terrain settings. These include a general driving programme, plus one for ice gravel and snow and three special off-road modes for mud and ruts sand and rock crawl. Ride height, engine torque response and all the traction control facilities are used automatically as appropriate brilliant.

Although the Ford/PSA 2.7-litre V6 turbo-diesel engine is a real gem in its class, powering all sorts of models from Jaguar, Ford, Peugeot, Citroen and Land Rover with 190bhp and 440Nm of torque in this instance, because of the four-wheel drive application and the weight of the Discovery, it is never going to be very frugal.

Official average fuel consumption is quoted as 30mpg but nobody I know has got anywhere near that. My test car returned just 23.5mpg, so the Discovery is an expensive vehicle to run.

With all that weight to carry you have to be forceful to get it underway but once in the cruise' it is smooth and quiet. With the high torque at low engine speed and with automatic transmission it copes well with heavy traffic conditions and it is very flexible and docile around town. Engine noise levels, except when pushed hard, are very quiet inside the cabin and road noise is virtually non-existent.

Owning this particular 4x4 gives the user big pluses if you live in the country or towing heavy loads or going hunting, shooting or fishing. But due to its size and running costs I'm not sure it is the most suitable vehicle for the city or town based school runs where so many of them seem to be used.

MILESTONES Land Rover Discovery 3 TDV6 HSE Price: £43,495 Engine:2.7-litre, V6, common-rail turbodiesel, 190bhp, 425Nm of torque. Performance: 112mph, 0-62mph 11 seconds, 30mpg (23.5mpg actual), CO2, 249 g/km.

Transmission: 6-speed automatic, permanent four-wheel drive, high/low ratio transfer box, locking differentials.

For: Executive refinement with the best off-road workhorse capabilities, flexible interior, and classy good looks.

Against: Price, running costs, lack of driver feedback and floating' performance on-road from the air suspension.