YOU can't knock Lexus for ambition. Its new IS saloon has to be the most enjoyable car to drive in its class, says its maker.

And remember, this is a class of mid-size executive cars dominated by the likes of... let's pick a brand at random... BMW.

Nobody ever said the latest BMW 3 Series was anything but good from behind the wheel, so Lexus is aiming high.

The luxury arm of Toyota introduced the first IS saloon in 1999, with the bolder second edition arriving in 2006.

Now comes version three, still bolder to behold and this time carrying kit in one model that's got the competition beaten. On paper, at least.

Buy the least expensive versions of the new IS, from £26,495, and you'll have a car powered by a conventional petrol engine. It's a hefty 2.5-litres and will struggle for sales in a class dominated by frugal diesels from Germany.

But for precisely £3,000 more you can upgrade your IS 250 to an IS 300h, which comes with a different petrol engine (though still a chunky 2.5-litres in size), but this time coupled to an electric motor and battery capable of shifting the car on current alone for a modest distance.

This lets Lexus boast of some alluring cost benefit figures for the mainly company car market the 300h is aimed at.

Figures like more than 64mpg in average use and, if you choose the cheapest hybrid model, a lack of road tax. The 300h in all its four versions will also please the company accountant and your bank balance with modest benefit-in-kind charges.

But remember the intention of turning this latest Lexus into a fine driver's car? Well, in one version it does a pretty decent job of meeting the brief, but not many drivers will be finding that out.

In the UK the petrol/electric hybrid IS is predicted to be five time more popular than the petrol-only model (800 sales plays 4,000 in 2014), with the extra three grand purchase price discounted by much kinder tax burdens for business users.

And it's the less expensive car that proves the better drive, by a convincing margin. It's quicker than its hybrid sibling and feels it.

More importantly, there's a fizz and brio about the car you don't enjoy in the hybrid. There's a downside, of course, and it comes at the pumps.

A quickish drive gave me 29mpg on the trip computer. Much the same sort of work in the hybrid 300h bumped this up to 44mpg; way less than the artificially produced official figure Lexus has to quote, but so much better than the IS 250 it's a no brainer at company HQ.

It does, however, leave a question hovering above the car. What about, say, taking a good BMW 3 Series diesel instead? It drives better, for sure, and will probably use less fuel but will cost more in overall running costs.

The new Lexus is notably smart inside, looking much posher than, for instance, the sombre interior of a 3 Series. It's also conspicuously well built, big in the back, marks very high in reliability surveys in previous versions and rides comfortably and in near silence.

But it's not quite the best car to drive in its class.