Motoring: Seized by M-plate mania? Choose your new car here: August is the worst month to buy a car. But since so many people are tempted by the new registration, Gavin Green offers a guide to cars at the top of their class

A quarter of all new cars in Britain are sold in August. This means that sensible people should not buy a car next month. However, rational decisions and motor cars rarely go together, so 500,000 buyers will be clamouring to own a car identical to the same model in July - except for a different letter at the start of the number plate.

August is a bad time to buy because salesmen are least receptive to haggling then; demand for new cars is strong, so why should they do you any favours? Also, come October, your gleaming M- plater may well be obsolete: manufacturers shift to making '95 model cars after the summer vacation. Trim changes are common, and brand-new models often come down the line. The August jamboree is a good way of clearing out old stock.

New models about to be superseded include the Granada (new and uglier one coming in September), the Range Rover (improved and pricier version in October), the Escort (new model on sale next spring) and the Jaguar XJ6/Sovereign/XJ12 (a prettier, more rounded model due in October).

Still, if you're bent on being the first in your neighbourhood with an M-car, here's what is worth buying. You should expect to get an on-road discount of about 10 per cent, although this varies depending on make and model.

Small car: Fiat Cinquecento, from pounds 5,199. Tiny, cute, easy to park, easy to drive, and amazingly space efficient: it can fit four adults. Great city car that should hold its value well. Also worth considering is the Skoda Favorit (from pounds 5,238), which is roomy and, now that Skoda is owned by VW, well made.

Supermini class: Renault Clio, from pounds 6,241. The French build the best small and medium-sized cars in the world, and this is France's best-seller. It is distinctive to look at, roomy, rides well, and makes Britain's top-selling Ford Fiesta seem amazingly crude. Also better than a Metro, because it's much roomier and more refined. Worth considering are: the Fiat Punto (from pounds 6,350), roomiest car in the sector, well made, cheeky looks and great value - let down only by roly-poly ride and rather vague steering.

Small Family Car: Citroen ZX, from pounds 8,965, and Peugeot 306, from pounds 8,850. The two best cars in this sector are essentially the same with different bodies and badges. Both are superb packages: roomy, lively and reliable with almost limo-standard rides. The ZX tends to be better value, though the 306 has more rear legroom and looks sharper.

Big Family Car: Ford Mondeo, from pounds 11,750. Scores on value, comfort and the ubiquity of dealers. Drawbacks are a shortage of rear headroom and a noisy, uncouth engine. Two great French family cars, the new Renault Laguna (from pounds 10,570) and the handsome Citroen Xantia (from pounds 11,150), make it a close contest. I would go for the Xantia, but the Mondeo is probably more sensible if you just want transport.

Executive cars: BMW 3-series, from pounds 14,295. One of the great cars. Fabulously responsible, handsome, fun to drive, and reliable, it keeps warding off newer challengers. It isn't that roomy, though, and the cheaper four-cylinder models (316, 318) aren't nearly as good as the pricier six-cylinder versions (320, 325). If you need more room, try its bigger brother, the BMW 5-series (from pounds 17,530), but only in six-cylinder guise. If you are not fussed about badges, the new Vauxhall Omega (from pounds 15,995) is surprisingly good and very roomy.

Pricey saloons: Jaguar XJ6, from pounds 26,950. Not as well built as its German rivals, but it still beats them for unadulterated luxury and the sense of well-being that only cabins crafted in Britain from walnut and leather seem to generate. But wait until October: the new XJ6 promises to be a big improvement over the current old-timer. If you can't wait, there's the recently facelifted Mercedes S-class (from pounds 38,050), an astonishingly agile behemoth; if you can, even better is the new aluminium- bodied Audi A8 (from pounds 34,499), a bold design that really is a step ahead of the pack and goes on sale here in October.

Four-Wheel Drive: Land Rover Discovery, from pounds 17,295. The Japanese can't seem to beat the Discovery, which offers a good-value 4x4 package that is refined on road and rugged off it. Don't buy the V8 petrol model (unless someone else is paying your fuel bills) or the 2.0 MPI, which is too gutless. The Discovery is one of the few vehicles that works better as a diesel.

Sports Car: Mazda MX-5, from pounds 14,495. Whenever I drive an MX-5, I'm astonished how much fun they are. Cute, in a retro MG sort of way, but reliable, the MX-5 is quick, handles sharply and is great to drive. If you've got more dough, the TVR Griffith ( pounds 32,995) is a handsome brute that makes wild V8 noises and goes very fast.

Estates/people carriers: Renault Espace, from pounds 16,350. The obvious choice if you need to haul seven people, this mould-breaker drives like a good saloon but with the added benefit of a nice high driving position, and all those seats (which can be removed). If you prefer a conventional estate, go for the reasonably priced and handsome Ford Mondeo estate (from pounds 13,245), which is roomy and practical as well as being a good drive - or, if your budget's bigger, a Mercedes-Benz E-class estate (from pounds 23,890), which will last longer than almost any other car.

Diesel cars: Any French diesel (Citroen or Peugeot in particular) is first rate. Any Ford, and some German, diesels are not. Special praise goes to the Peugeot 306 (from pounds 9,100), Citroen ZX (from pounds 8,965), Citroen AX (from pounds 6,700), VW Golf TDi ( pounds 12,699), Vauxhall Corsa TD ( pounds 8,390) and Vauxhall Omega 2.5 TD (from pounds 18,500).

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