TOYOTA must be quietly confident that years of developing cars with electric motors helping out their petrol engines is going to pay off - big time.

And nowhere more decisively than in the Yaris, the company's small family car that has just been comprehensively updated without actually producing an all-new version.

Around half of the expected sales will still go to an all-petrol model, with a new and larger engine aimed at improving real world economy, but the hybrid petrol/electric version is destined for great things.

Like capturing four of every 10 new Yaris sales, and that with a car starting at a not inconsiderable £15,995 for an entry level hybrid, which only a tiny one per cent of new Yaris buyers will take.

Most will upgrade to an Icon level car, happy to find £17,595 or settle for increased monthly payments on the personal contract plans that nearly everyone uses today to put themselves into a new car every three years or so.

Don't fancy the added expense of a hybrid, despite its official 85.6mpg and 75g/km from the 98bhp powertrain? Then Toyota will point you towards the two purely petrol models, using either the 1.0-litre unit from the old car or a new 1.5-litre, up in capacity from the previous 1.3-litre in the hunt for better real world economy, soon to be reflected in new and more realistic official consumption tests.

Which is a happy admission that working an engine more gently can be better for fuel frugality than flogging a little one half to death.

The new range starts at £12,495 for a base spec 1.0-litre. Prices have risen by up to £500 across the range but extra standard kit can be blamed for around £400 of that, says Toyota.

This includes automatic emergency braking which will slow the car if it senses an accident in the offing and the driver fails to brake, automatic main beam selection and lane departure warning by polite bleeps.

If you already own a Yaris you might spot that the French-built new one has a fresh and more aggressive face, modestly smoothed over rear and a dash of low down chrome along the side, all with the intention of adding a touch of style.

The inside has been similarly gone over, with new trim and clearer instruments and a centrally mounted screen that can conjure up a host of clever additions to add practicality to your journey, including satellite navigation on some versions, or help pass the time.

One app called 'glass of water' shows just that and rewards a smooth driver by not slopping its imaginary contents over the lip. Yes, really.

Much more important is the drive to make the hybrid model - with its tax busting 75g/km emissions - even more attractive to the sort of potential owner moving down from a bigger car yet expecting no less comfort.

So the Toyota engineers have been all over it in a detailed way, paying attention to items like the exhaust silencer, shock absorbers, power steering and the way engine is mounted in the car.

The result is a resounding success, producing a Yaris that is deliciously quiet at any sensible speed and almost silent at a town trundle on the uniformly wonderful roads of the Netherlands, where the newcomer was launched to the press.

Which brings us to a bit of a poser. The non-hybrid models, including the best selling 1.5-litre model, have not been treated to the hush-hush treatment. And it shows, sadly.

On the same roads that produced smiles from the hybrid, the newly engined 1.5 was loads louder, especially under a fuller throttle, which it needed rather a lot. It did, though, produce precisely 50mpg. With 110bhp on call it is usefully brisk on paper (11.0 seconds to 62mph, 109mph) but you won't want to explore the edges of the performance envelope.

That counts as a result, if some way behind the 60mpg from the hybrid, which a cunning black box temporarily attached to our car showed we had been moving under electric power alone for half our two hour journey on Dutch main roads and alongside tulip carpeted bulb fields.

The least powerful Yaris with its unchanged 1.0 litre engine managed 48mpg and produced the sort of egg-me-on noises common to most three cylinder engines. Most owners, one guesses, might be happy indeed in this model.

Modest performance figures (96mph, 15.3 seconds to 62mph) are offset by 99g/km emissions and 65.7mpg overall official consumption - although falling to 48mph on our route.

The likely favourite Icon trim includes air conditioning, cruise control, rear view camera and alloy wheels and costs £14,495 with the 1.0 litre engine, £15,295 with the 1.5 litre and £17,595 as a hybrid.