Ford was quite right not to create a diesel-engined Focus until its latest-generation TDCi unit was available. The older and very much inferior TDDi was coming to the end of its life anyway, and might well have created a perception of Focus diesels as being slow, noisy and not worth bothering with.What Ford has produced instead is an exceptionally appealing machine. In two-litre form the new engine makes the Mondeo diesel a fine car, and if anything the 1.8-litre Focus is even better. With less body structure to absorb the inevitable low-speed rattle, it isn't especially quiet first thing in the morning, but at cruising speeds the sound becomes a distant thrum and you can get on with enjoying the combination of performance and economy.There's certainly more than enough of the former for normal purposes. Mid-range power is impressive, and makes whizzing along deserted country roads a relaxed and enjoyable affair. It so happened that my week behind the wheel involved quite a lot of this sort of thing, which may be why I wasn't quite able to squeeze 500 miles from a tankful. If I'd been doing more motorway driving I reckon that kind of range would be achieved quite easily.As ever, the extra weight of the diesel engine has an effect on the way the car handles, but Ford's chassis people have done a fine job of coping with this. There is quite a lot of body movement, but it's always well controlled. The balance between ride and handling is splendid.Well, with one exception, perhaps. In hatchback form (though less so as a saloon or estate) the Focus has always been nimble through the bends, largely on account of its clever rear suspension which allows the tail of the car to follow the front and reduce the possibility of oversteer.In the case of the TDCi I suspect there is more body roll than was envisaged when the rear suspension was being devised - which would have happened, let's not forget, several years before the diesel version went into development. On the whole there is no problem, but if you turn into a corner energetically on a damp road there is a definite steering input from the rear. While this was never enough, during the test, to send the car sideways, there were occasions when I had to straighten up the steering sharpish to prevent the nose tucking far more tightly into the bend than I wanted it to.After the initial shock of Ford's "Cutting Edge" styling, the Focus now seems more restful on the eye than it was when it first appeared. That includes the interior view - I no longer find all the fancy lines as distracting as I did in the early days, though this might be partly to do with the dark trim colours of the test car and partly a result of having driven a good many cars recently in which the interior design has been taken several steps further.By comparison, the Focus now seems quite straightforward inside. A case in point is the radio. I can't believe this is the first car I've driven which includes a display telling you what programme you are listening to, but it's the first time I've been conscious of it. A pretty up-to-date system, then - but at the same time one with proper-sized controls which only need to be glanced at to understand their operation. Within the last few weeks I've driven at least one car whose radio I didn't even know how to switch on for the first two days.Excellent interior space, an adjustable steering wheel and seats which are purposeful without being flashy all combined to make the Focus a comfortable car to spend time in, even if in this specification it is hardly a luxurious one. But the star of the show was undoubtedly that TDCi engine, which has immediately made the Focus one of the best diesel cars of its size on the market.Second opinion: I drew the motorway straw, and found this to be the best Focus I've driven so far on the long mile-eating hauls. Oddly enough, it wasn't the economy or the easy cruising gait that made the biggest impression, but the mid-range torque. The 1.8-litre TDCi produces 184lb/ft at 1850rpm, which means that this model darts away when there's a gap in the motorway traffic, and really gets stuck in on the long climbs. That same attribute allows it, when you also take advantage of the generally very smart cornering, to shrug off annoying on-the-back-bumper characters who don't appreciate just how well the car can go on more twisty A- and B-class roads. I'd have liked more steering wheel adjustment, although that radio is a hoot, telling you not just what individual programme you're listening to, but also the presenter's name, what kind of listening it offers, and what programme comes next. Classical music, for instance, is identified by a line of notes rushing out of a grand piano. Ross Finlay.