What is it?
Quite expensive, that's what. This diesel version of the facelifted BMW 1 Series costs almost as much as the flagship M135i. Your £29,800 doesn’t bag you a melodious straight six, either; instead this 125d M Sport packs a 2.0-litre four-cylinder diesel.
Cylinder count isn’t always everything, however, and this engine is one of BMW’s latest. Its head and block are of weight-reducing aluminium and its specification sheet would satisfy any high-performance engine builder in the land. Forged con rods, a forged steel crank, lightweight pistons and multi-stage turbocharging are among the highlights. The net result is a hefty 221bhp and 332lb ft, sufficient to propel the 125d from 0-62mph in 6.3 seconds.
You can only get this range-topping diesel with the Sport version of the well-proven eight-speed ZF automatic gearbox, which has been upgraded further. It now looks at the car’s navigation data, even when there’s no planned route, to help select the appropriate gear for the road ahead.
In addition to the new engine and the revisions to the gearbox, there have been some cosmetic updates. Externally, the 1 Series gets restyled bumpers and much sleeker rear light clusters. Inside, you’ll find some new chrome and gloss-black trims, which lift the cabin ambience slightly. Standard kit is adequate and includes single-zone climate control, a DAB radio and the iDrive system with 6.5in screen. As of September, sat-nav will also be standard across the BMW range.