When you're buying a second-hand Mercedes, read the service book

Image. In the used-car business a good image makes life a lot easier.And in the case of Mercedes, it makes the German car a sensible and safe, if expensive used buy. For a car that in its native land leads a double life as the nation's favourite taxi, you might think that image would be hard to come by. But not a bit of it. All the qualities that are required to keep a Hackney carriage on the road - reliability, comfort and solidity - are standard features on the Mercedes, especially the medium- sized models like the W123 and its successor, the E class. Not opulent like the huge S class, or remotely sporty like the SLs, these models won't ever let you down. With the arrival of the new E class, there has never been a better time to consider one of these classy saloons.

The W123, also referred to as the 200 series, lasted 10 years, staying in production from 1976 to 1986, although used examples are set to be with us well into the next century. Build quality on these cars was nothing short of remarkable. Everything about them is heavy, from the minimum 3000 pound kerb weight to the Fort Knox doors - and, it has to be said, the rock hard seats.

Firmness is part of the Mercedes interior experience. One flick of the precise switchgear proves that the flimsiest thing on board is the driver. Not surprisingly there is a sixth digit on the mileometer to cope with the inevitable multi thousand mileage. So beware owners who lie about the true mileage, or the car's previous life as a private hire taxi.

When it comes to choosing a model, the 200 is slow, the 230E pleasant and the six-cylinder 280E the best. Diesels are deservedly popular, but are painfully slow. TE estate models are the most up-market of load luggers and easily eclipse the common Volvo.

The W124, more commonly called the E class, carried on from where it's predecessor left off, as a relaxing, sophisticated and prestigious package. It was a big improvement, with more modern styling, lighter bodies and better performance. The range steadily grew to include more engine options. ABS braking was standardised and owners could stamp their own personality on the cars by ordering "Sportline" special equipment. Further model upgrades occurred in 1992, when the driver's airbag was standardised and new 24- valve six-cylinder engines were installed. Once again the 230E is the best budget model, but six cylinders on the 260 and 300 make even more sense.

Buying a middleweight Mercedes like this only requires that you do one thing: read the service book. It there isn't one, worry. An E series with a patchy history is best left alone. You can be more lenient with the older W123, but there must be evidence (lots of receipts) that the last few owners were prepared to spend money on servicing and parts. Lack of attention is the Mercedes' only enemy and then things will start to go expensively wrong. Always buy an automatic, but don't pick an unwise beige, dull or watery colour scheme which looks awful and can knock hundreds off the resale value. Sunroof and alloy wheels also make selling a Merc on even easier. So if the W123/4 you like looks pristine, drives quietly and has a history then there is nothing to worry about, in theory.

In practice, I stumbled across perhaps the most remarkable testament to the Mercedes marque when I visited a friend and his recently acquired W123. Parked in a field for a year, it had a patchy history and poor prospects. My friend bought it for pounds 250 and towed it away. After a minor service, a new battery and a steam clean, it runs and drives like a two- year-old despite the 120,000 miles.

Maybe he was lucky, but there are plenty of similar cars advertised at around pounds 1,500 to pounds 2,000 in quite remarkable condition. The most you will pay is pounds 5,000 for a 1986 TE estate unless the genuine mileage is spectacularly low. The trick is avoiding the ones that have recently been retired from the mini cab circuit.

Looking for E-class cars that I could believe in, I visited Western Mercedes Benz in Edinburgh. They had a 300E for pounds 11,495 with the ideal specifications of an automatic gearbox and alloy wheels. It was a two-owner example with full service history, and mileage a careful 75,000. Down south, Dick Lovett had another 1988 E Class, 230 TE estate. Seven seats, automatic and air conditioning, almost perfect, for a reasonable pounds 12,995. At Brunswick in Croydon pounds 32,995 could get last year's E320 with all mod cons and a tiny 9,000 mileage.

For cost-effective Mercedes shopping you have to consider private sellers or specialists. At Kenton in north London there was a good selection of E-class cars. Their diesel estates started at pounds 10,395 for a 1987 model and rose to pounds 15,995 for a 1990 300E 24-valve with leather and service history. There was even a 1983 280SE at pounds 4,995.

For something more unusual, Stadium Cars in Glasgow had a tarted up, F registered 300E at a mere pounds 9,995. The good news was a full Mercedes service history, but not everyone would appreciate its body kit, even if it is a factory approved AMG add on. An E class, or in fact any Mercedes, will always looks better without any adornment. Right car, nice price, wrong image.

Western Mercedes Benz: 0131-443 6091

Stadium Cars: 0141- 647 5878

Dick Lovett: 01793 615000

Brunswick: 0181-760 0210

Kenton: 0181-907 7445