MOST of us are insulated mentally against rather optimistic claims by salesman, manufacturers and the like.

So when I read that this Vauxhall Astra was fitted with the new ‘whisper' diesel engine, I took the info with a proverbial pinch of salt.

It's true diesels have got steadily quieter over the years, with a noticeable decrease in that agricultural clatter at tick-over.

But could this be the breakthrough that put its refinement in line with petrol engines?

Well, it didn't take many miles to be impressed, not only by the general hush but also the mid-range acceleration.

With 134bhp being squeezed out of the 1.6-litre engine, performance is ahead of most rivals and what's more the power is easily accessible without having to drop down through the gears.

Bags of torque means there's little need to wind up the revs. If you choose to approach the red line the engine's distant hum does become more audible and less pleasant.

The current shape Astra is an attractive looking five-door hatch with as much cabin space as most of the opposition and a boot that can swallow up a useful 370 litres of luggage.

If you are willing to sacrifice the rear seats by flipping them down, cargo room expands to 1,210 litres. Bags, however, have to be lifted over a lip into the boot.

I drove the SRi Nav version which includes such goodies as sat nav, sports front seats, daytime running LED lights, hill start assist and electric front and rear window lifts. Price is £21,480.

There are seven levels of trim to choose from and even the entry version has cruise control and air con.

The cabin received a thorough makeover for this latest model with the fascia receiving special attention. Soft, easy-to-the-touch soft plastics are used and the layout is simplified. Controls are fewer and better marked. There's still a bit too much dark plastic around, but the effect is classier than of old.

While the SRi makes no pretence at being a hot hatch, it certainly delivers plenty of driver satisfaction. Cornering is tidy and leach-like with light, if rather lifeless, steering.

Bumps are ironed out much better than previous Astras and the ride is composed and compliant without being over-soft, so roll angles are kept well within check.

Despite ample power, the six-speed manual SRi is miserly when it comes to running costs. The official combined fuel consumption is a reasonable 72.4mpg, which equates to a real-world figure of 50-plus mpg. During my test I saw a best of 58mpg during a lengthy but gentle cross-country drive.

With CO2 emissions of just 103g/km, road tax is pegged at £20 and company car drivers will have minimal overheads.