Motoring: Urban farmers have a field day: James Ruppert surveys the latest cash crop

Once upon a time, buying an old four-wheel-drive vehicle meant standing wellie-deep in a muddy field arguing with a farmer about how little his Land Rover was worth. These days, buyers receive the full showroom treatment and are offered a wide choice of new and used models that are safer, more durable and easier to drive than their ancestors and have the best residual values of any class.

All good reasons for buying a four- wheel-drive vehicle? Yes, but there are also sound reasons against. Four-wheel drive is fashionable and fine in theory, but in practice it can be a pain. Vehicles are great on rough terrain and for such specific tasks as towing, but fuel economy is dismal, the on-road ride less than comfortable, and servicing and repairs are costly.

If you still fancy one, the first question is: which one? The gentrification of the off-roader began in 1970 with the Range Rover beloved of the ruling classes. There are lots around from about pounds 3,000. Five-door automatic Vogues are the ones to buy; nothing else comes close. Mercedes-Benz tried, with the G-Wagen, but that was a bit too army-surplus in execution and was unpopular as a result.

Then came the middle-class Mitsubishi Shoguns, Nissan Patrols, Toyota Landcruisers and Isuzu Troopers - Japanese, supremely competent and well- built. Land Rover pitched in to this market with the Discovery, basically a Range Rover in drag. Top of the urban farmer's wish-list is a five-door, diesel-powered Tdi, which depreciates very slowly.

Finally, there is the purely recreational, four-by-four-as- fashion-accessory sector, again dominated by Japan. The Daihatsu Sportrak is an also-ran compared with the Suzuki Vitara, which is the XR3i of the Nineties, with limited off-road ability and massive poseur-appeal.

On the cheap-and-cheerful front there are low-tech, low- cost entries, the Lada Niva from Russia (competent, but crude), the Dacia from Romania (Renault-powered and rubbish), and Mahindra, an Indian version of the Jeep (rare and painfully sluggish).

Once you have found a likely looking model, how do you determine if it is worth buying? First, find out how it has been used. Ideally, it should have been an urban vehicle dealing with nothing more taxing than the incline at a Tesco car park. Tow bars hint at a tough life, which puts a strain on the engine and transmission. Look at the sills and underneath at the chassis for signs of damage and corrosion.

Before the test drive, investigate how the four-wheel-drive system is operated, and make sure you try it out. On high- mileage vehicles, the transmission will whine and be difficult to use.

Allowing myself a pathetically small budget, I arrived at Fenland 4x4 near Wisbech to find that pounds 1,595 would buy a SJ410, effectively the Vitara's dad. These are Jeep-like playthings with a reputation for toppling over and rusting to bits. This hardtop dated from 1983 and Fenland said frankly that that the vehicle required some attention. The body had started to corrode and a new gearbox was needed urgently. The price was by now eminently negotiable and it would be a sold-as-seen sale.

Fenland thought I would be much better off with a later SJ413. More stable, better quality, it also had bull bars and was priced at pounds 3,495. But that would not have persuaded the poseur, who would have been happier at Ray Powell in Thetford, which had a blinding white 11,000-mile Vitara with all the knobs on. Never mind the ubiquitous bull bar, there was a body kit, wide wheels and roof rack, all for pounds 10,995.

The Essex specialist Boundary Garage had plenty of Japanese heavyweights, starting with an F-registered Nissan Patrol at pounds 6,999, which seemed to have led a comfortable on-road life. The Patrol, however, doesn't quite look the part on the school run, nor does it have the reputation of, say, the Isuzu Trooper, one of the most civilised four- wheel-drive vehicles. A G-registered example with every creature comfort (air-conditioning, heated seats, cruise control, plus nine seats) was on offer for pounds 9,999.

Over at Motorworld in Oxford it was interesting to see how close in specification and pricing Mitsubishi Shoguns come to our own dear old Range Rover. These Shoguns get the thumbs-up from those in the know, and pounds 21,999 would have bought a 1992 long-wheelbase, seven-seat turbodiesel with 22,000 miles on the clock. If you make do with a 1990 model with a less curvaceous shape but identical spec and 40,000 miles, you will pay pounds 14,499.

Impressive as the Japanese contingent may be, the ultimate off-roaders still come with a Land Rover badge. The Discovery is a best seller, but used models can usually be found only on main- agent forecourts because owners prefer part-exchanges.

Lancasters in Reading had an impressive line-up of five-door Tdi models from 1992-93. You need pounds 20,000 to join the Discovery club at this level. The only 'affordable' example I found was at Mann Egerton, of Norwich, which was asking pounds 10,995 for a 1990 three-door, gas- guzzling V8, which had a grubby interior but only 15,000 miles on the clock. The least desirable or practical model, it none the less has unrivalled off-road ability.

For that money, of course, you can get a Range Rover. At Woolhampton Sales in Berkshire, a Vogue EFi with macho bull bars, auxiliary lights, 70,000 miles on the clock and numerous interior creature comforts cost just pounds 8,495.

Perfect for the farmer who has just flogged his old Land Rover.

(Photograph omitted)