There are, however, sound reasons for giving the hitherto wholly predictable and ultimately underwhelming Corsa an engine capable of becoming a conversation piece. With three cylinders instead of four, the engine's moving parts generate less friction because there are fewer of them. And because less heat is lost through fewer, bigger cylinders than through more, smaller ones, there's more energy left to propel the car. A three-cylinder engine, then, has the potential to be very economical.
If this engine were indeed powering a lawnmower, it would be a hi-tech one. The motor is a masterpiece of miniaturisation, with tiny tappets to open the 12 valves, and an electronic control unit so small that it's built right into the intake manifold. Technophiles will love it; so should motorcyclists, whose favoured engines the Vauxhall's closely resembles.
But all this, I fear, may be lost on the average Corsa buyer. After all, to date the Corsa has not been a car to delight the driving enthusiast, despite its cute curves and an admirably ergonomic interior. Small cars are meant to be fun to drive, which means making them sharp and nippy, but Corsas have managed to be neither. Few small cars feel stodgier.
The reason for this is that Vauxhall has been bound by an engineering credo which calls for all its cars to be able to do an emergency lane- change manoeuvre at somewhere near its maximum speed while containing a full load of people and chattels, without even a novice driver losing control. Though well-intentioned, if patronising, this is not a recipe for an entertaining small car. To its credit, Vauxhall has finally woken up to this and has packed the Corsa off to Lotus for some suspension aerobics.
Lotus moved a pivot-point here, fiddled with some springs there, and banished the feeling of flab. So, after the surprise of the new engine's sound has abated, you can enjoy a Corsa which both steers more incisively and rides over bumps better. It's no match here for a Ford Ka or the Peugeot 106/Citroen Saxo twins, but it's a big improvement. Soon there'll be a neat power-steering system available, too, which uses an electric motor attached to the steering column.
These improvements apply to the entire Corsa range, which includes 1.2, 1.4 and sporty 1.6-litre four cylinder versions, and some diesels, as well as the 1.0-litre three-cylinder. All are recognisable by a new front grille with a chrome V, as well as detail changes to trim. But it's that tiny new engine that draws your interest the most. It's not powerful - just 55bhp - but it is smooth, willing and able to achieve much higher revs than its deep, almost Porsche 911-like engine note suggests.
The only real snag is that the secret of the smoothness, a heavy flywheel, makes the engine slow to lose speed between upward gear changes, so you have to be patient to avoid a jerk. This encourages a laid-back driving style, which suits the meagre performance well. And if you get frustrated by the lack of pace, you can console yourself with the engine's remarkable economy. Driving it as fast and as hard as I could make the little Corsa go, I couldn't get it to travel fewer than 39 miles on a gallon of petrol.
So here, at last, is a Corsa with some of the personality its looks always promised. But before we get too carried away with the forward thinking of Vauxhall's General Motors parent, it's worth remembering that the Japanese have been building tiny three-cylinder engines for years. It just goes to show that there's nothing new under the rising sun.
The new engine appears first in the Corsa Sting, a limited-edition model based on the entry-level Corsa Merit three-door but with three-spoke alloy wheels, a sunroof and metallic paint. Other trim levels will follow.
VAUXHALL CORSA STING
Price: pounds 8,400 on the road Engine: 973cc, three cylinders, 12 valves, 55bhp at 5,600rpm; five-speed gearbox, front-wheel drive.
Performance: top speed, 93mph; 0-60mph in 17.6 sec.
Fuel consumption: 45-49mpg
Citroen Saxo 1.1X, pounds 8,195 OTR: Well-priced, comfortable and fun to drive. Same goes for the similar Peugeot 106 1.1 XL (pounds 8,505 OTR).
Fiat Punto 55S, pounds 7,622: Good value, distinctive looks but lacks refinement. Revised Punto comes in June.
Ford Ka, pounds 8,015 OTR: To look at, as radical as a Mini was back in 1959. To drive, pure entertainment. Best small car on offer today.
Nissan Micra 1.0 Shape, pounds 7,995 OTR: Round and cuddly like the Corsa, but too Toytown for some.
Volkswagen Polo 1.0L, pounds 7,990 OTR: As slow as the Corsa, but bearable. Looks neat, feels solid.