OK, we will admit that the sound isn't quite up there with an inline six, and there is a light tap-tap rattle at idle that is vaguely irritating (but given that a Golf GTI has more than a whiff of diesel about the noise it makes at idle, we'll forgive the 1 Series that one), but overall it's actually a pleasant-sounding car.
And, however much we wish it weren't so, cars in this market - performance-oriented but still everyday cars for people with limited resources - do need to provide ever-more in the way of fuel economy. So, with regret we're inclined to take the claimed 42.8mpg (about 35mpg in our time with it) over an extra couple of cylinders and a nicer noise.
tried the bigger brother of this engine in the BMW Z4 and we know that it makes what is otherwise a distinctly average car palpably better. In the 1 Series, it makes what is an already thoroughly decent car into a borderline cracking one.
Throwing aside the question of looks (these things are of course subjective, but it is hard to love the styling of a 125i, even with the beefy M Sport addenda), the latest 1 series is a pretty good bet. The Interior is now up there with what you expect of a mini BMW, being well laid-out and reasonably well put together, while the packaging is also much better than it used to be, with a decent boot and space for four actual adult-sized people.
With the 125i M Sport you also get a chunky bumper, spoiler and side skirt combo, along with twin tailpipes and, inside, flashes of aluminium-esque trim and leather sports seats. In addition there are 18-inch wheels and beefier brakes, with natty M Sport calipers.
The 1 Series still isn't all that exciting dynamically, then, but that's in comparison with other BMWs; against its front- and four-wheel-drive rivals the advantages in agility of the rear wheels doing the driving and the fronts doing the steering are palpable.
In short, the 125i has a mini sports saloon feel to it that more conventional C segment hot hatch rivals could not hope to emulate, and the punchy, efficient engine combined with a well-weighted (if a teensy bit notchy) six-speed manual serve to highlight that.
the Renaultsport Megane, but it presents a more mature, subtle alternative to the fast hatch norm.
With the basic list price a small but significant notch below the Golf GTI (perhaps its closest conceptual rival; an everyday performance car with a mature, sensible edge) the 125i represents a genuine, unique and good-value alternative to a mainstream hot hatch.
And if you really need six-cylinder power from your 1 Series you can always wait (and save up for) the forthcoming M135i. Then again you could pop along to the PH classifieds and have a butcher's at previously loved 130is...
BMW 125i M SPORT
Engine: 1,997cc 4-cylinder, turbo
Power (hp): 218hp @ 5,000rpm
Torque (lb ft): 228 @ 1,350-4,800rpm
0-62mph: 6.5 sec
Top speed: 151mph
MPG: 42.8 (NEDC combined)