As with so much else about the 3, it’s the Mini that sets the benchmark in this department – and because BMW supplies the diesel engines to Oxford, that means the French car has to go up against the Cooper D’s cutting-edge B37 1.5-litre triple on power and the Cooper SD’s 2.0-litre four on price.
As respectable as PSA’s 1.6 BlueHDi unit undeniably is, it’s not quite in the same league as either of those Mini options; the first is a remarkable combination of efficiency and polish, while the second makes the Mini far more responsive and rapid than the 3 tested here ever had a chance of being.
Putting the class-leading question to bed early leaves us free to focus on the positives here, of which there are many.
As we’d hoped, the 1.6-litre motor is a likeable all-rounder. It’s relatively refined, keen to rev, parsimonious to a fault and yet decently spirited with it. True, that sense of spirit didn’t quite translate into the claimed 0-62mph time, but the 3 was slightly hampered on the day we figured it by damp conditions and an anxiousness for getting all of its 210lb ft down early.
Nevertheless, under 10.0sec for the 0-60mph sprint is sufficient for the car not to feel ponderous away from the line (the common diesel-engined supermini malaise), and that healthy peak torque figure results in pleasing in-gear flexibility – even from the predictably lengthy final ratio.
The six-speed gearbox itself is a maladroit old thing. It’s not unpleasant to use but is a little too long in throw and a bit short on sophistication, given the competition.
True MPG evaluation wasn’t possible at the time of testing – a shame, because in the 47 miles of fairly merciless Millbrook treatment, the 3 returned 29.3mpg, making the 67.4mpg trip computer average we registered on the gentle 80-mile drive home all the more creditable.