Bargains do not often come in Rolls-Royce-sized packages. To most Vauxhall Cavalier or Toyota Corolla owners, the idea of paying half the cost of a suburban semi for a mere set of a wheels - and a second-hand set at that - looks a lot more like lunacy than anything resembling financial prudence.

Yet for those in Britain who only buy the world's most luxurious cars (and there are about 30,000 of them annually, even in a recession), two to five-year-old BMWs, Bentleys, Lexuses and Jaguars are cheaper - as a percentage of their original list prices - than a traditional economy car such as a Mini - and the slump has widened the gap.

Top People's cars struggle to find new owners once they have a few miles on the clock, and prices now are as low as they have ever been.

Today's BMW 750i, the Munich company's top saloon powered by a 5.0 litre V12 engine, costs more than pounds 53,250 out of the showroom. By the time it has number plates and delivery charges paid, it costs pounds 54,000. Even if the buyer remembers to negotiate a discount - and a surprising number don't - most of pounds 50,000 will have been shelled out by the time the new set of wheels hits the street.

But had the same buyer been prepared to buy secondhand, he or she would have found a surprisingly large selection of three-year-old cars for sale with 20,000 to 40,000 miles on the clock, costing less than pounds 25,000, or about 45 per cent of the car's on-road cost when new. Older and higher mileage cars, many still immaculate, come even cheaper.

By way of contrast, a Mini Mayfair, currently listed at pounds 6,395, will have a private sale value about pounds 4,000, or well over 60 per cent of its original price, after three years and 30,000 miles. In this sense the most luxurious vehicles in Britain offer better value as used cars than the ubiquitous Mini.

There are excellent used examples scattered across Britain at rather less than half their original 1989 or 1990 prices. Mercedes-Benzes tend to hold their value better than the rest, but even in this firm's range, it is the cars at the top of the price scale that lose most value in the early years.

'When you tell people how rapidly prices of top luxury cars decline, they assume it's because lots of companies are going bust in the recession,' says Derek Bright, who deals in used Rolls, Mercedes and Jaguars from premises near Bath. 'But it isn't that at all. Cars like this have always declined fast in recent years, but the problem is worse now because of an oversupply of new luxury cars into the market during the boom three or four years ago.'

Despite their early price falls and high upkeep, top-end luxury cars have surprisingly practical attributes, some experts claim. All cars in this price range were beautifully built in the first place, and most have been maintained regardless of cost. Second, after three or four years, the price-falls slow. The BMW, which sheds pounds 28,000 of its value in the first three years, will probably lose less than half as much over the successive three. Third is infrequency of model change: the Rolls/Bentley shape has been current since the early Eighties and will continue into the later Nineties.

Finally, high servicing costs can be beaten. Non-franchised specialist firms with expertise in looking after the top marques are surprisingly thick on the ground. Often, they are run by factory-trained technicians who left the official organisation to run their own businesses.

Ian Briggs, a Midlands Mercedes specialist, is a good example. 'We reckon to know as much about the inner workings of the cars as most official dealers,' he says, 'though occasionally we refer customers to the supplying dealer when complicated electronics go wrong. Our customers score because we have cheap labour rates - we charge pounds 22 an hour against the local dealer's pounds 40 plus - and our spares prices are often lower, too.'

The conclusion must be that as secondhand buys, super-luxury cars make much more sense than the new ones which are now the preserve of boardroom heavyweights. Here are some prominent models to consider, each with the virtue of being fairly easily available. Prices and information are supplied by Car Choice, the monthly car buyers' magazine

BMW 750i An excellent car in almost every respect, save that the critics think its 5.0 litre V12 engine is not quite as smooth as rival 5.3 litre Jaguar unit. Beautifully built and equipped, though the gadget-packed cabin can be a little intimidating for the uninitiated. Towering performance and lots of cabin room. Enormous early depreciation means late Eighties versions start below pounds 20,000.

Lexus LS400 Toyota of Japan so want to challenge the big names of the luxury market that they have established a special brand name to do it. First product is the LS400 saloon now three years old here, but other Lexus models are coming. Not the handsomest big saloon, but quality and reliability right up to the highest German standards. Cheapest ones now just under pounds 20,000; new price still very reasonable at pounds 39,000.

Rolls-Royce Silver Spirit/Bentley Mulsanne Traditional Brit can no longer claim to be the best car in the world, but stately quality, silence and ultra-soft ride still make them special. High proportion of hand manufacture cannot match millimetre-perfect robot-build of Merc and BMW, but still very rugged. New prices are stratospheric, but a good value car with many years left in it can be had for under pounds 30,000.

Mercedes-Benz 500 SE The just-superseded Mercedes S, which toppled Rolls-Royce during the Eighties, is plentiful enough to make for a lively market and exclusive enough to turn heads. Known for its durability, the car comes in two different wheelbases (SE or SEL) and with a variety of engines ranging from 3.0-litre six to a high-performance 5.6 litre V8. Pick of the crop is probably the 500 SE. Prices for good late-Eighties examples of either model with less than 50,000 miles start below pounds 18,000.

Rare among the biggest luxury cars is the Mercedes SEC, a large and beautiful coupe version of the S-class saloon. Recently superseded by a hugely expensive and much uglier model, the pre-1992 SEC is already showing signs of becoming a classic shape. Engine range and prices are much the same as the S-class saloons.

Jaguar XJ6 Since the launch of the 'new shape' Jaguar in 1986, the Coventry firm has barely had an entrant in the super-luxury saloon class. The six-cylinder cars do not really have the class of a Bentley or a Mercedes S-class; the old-shape V12 is rare and feels comfortable but old. Still, if a Jaguar is your desire, they're great value. If you've pounds 12,000 to spend you'll be knee-deep in 4.0 litre XJ6 autos (the ones to go for), and a recent XJ12 should come your way at this price, too.

The ubiquitous Jaguar XJS is still a remarkably fast and refined machine, especially in V12 form. Owners horrified at the prospect of fuel consumption below 16mpg are better off with the 3.6-litre six-cylinder version. The pick of the coupe crop, with either engine, comes at about pounds 12,000. If you want a convertible, though, you'll have to find pounds 20,000.

(Photographs omitted)

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