Three years ago BMW launched the most powerful version of their 1-series model. Dubbed the M135i, it offered a whopping 316 bhp from its twin-turbo straight six engine.

Fast forward to 2015 and the refreshed model - along with a modest power hike of 6 bhp - gets new headlights, LED rear lights, updated bumpers and 18-inch alloys. Perhaps more significant though are the raft of improvements issued that are shared with all new 1-series models. These include additional EfficientDynamics technologies fitted as standard, a revised 6.5-inch Control Display infotainment system (8.8-inch with optional Professional Navigation) and refreshed interior cabin.

On the road the M135i is every bit as fast and engaging as its predecessor - with the free-revving turbocharged straight-six motor feeling extremely strong in any gear, at any speed. Power has been increased in the new model to 322 bhp, with peak torque of 450Nm, enabling a 0-62mph time of just 4.9 seconds (with eight-speed ZF auto), yet the ability to return 37.7mpg.

However, the impressive figures fail to convey just how responsive the M135i feels, no doubt due to all that torque coming in a low 1,300 rpm. The six-speed manual box can be a bit notchy though, but luckily the brilliant eight-speed ZF auto is also offered which provides slick smooth shifts (even around town) and makes it incredibly easy to manage the car’s prodigious performance.

Just like its predecessor, the new M135i rewards the driver with taught balanced handling and positive and crisp turn-in. True, it’s not quite as focused or pure (particularly the steering) as a thoroughbred BMW M car and it would start to get a bit ragged when driven at ten-tenths on a track, but it’s still a very capable hot-hatch and as good as key rivals from VW, Audi and Mercedes.

With regards to refinement, being a sporting model, the M135i does have a firm ride and the large wheels can drum up noticeable amounts of tyre noise on coarser road surfaces, but for the most part this is overshadowed by the glorious and intoxicating six-cylinder wail.

All BMWs now get sat-nav as standard and DAB radio, leather and Bluetooth are also included on the M135i, as is the emergency e-Call system, which launched last year. The options list encompasses items for comfort, functionality and entertainment. These include: electrically adjustable and heated seats for the driver and front passenger, two-zone automatic air conditioning, a heated steering wheel and the Harman Kardon Hi-Fi system, complete with 12 loudspeakers and a digital amplifier with 360-watt output.

The driver-focused cockpit of the new BMW 1-Series is an even more welcoming, sporty, comfortable place to sit, thanks to enhancements to the design, and the materials and fabrics used. Numerous M-specific features such as the leather steering wheel and the use of the M135i logo also give a separate identity to this sporting model.

Along with an updated infotainment screen, both the air vents and the controls for the radio and the automatic air conditioning now feature high-quality chrome surrounds. The radio and automatic air conditioning keypads, meanwhile, are now set against high-gloss black panelling. All new BMW 1-Series models are optionally available with a 40:20:40 split rear seat backrest: folding one or more of the sections allows boot capacity to be increased in stages from 360 to 1,200-litres.

Verdict:

BMW’s 135i sits halfway between a regular 1-series and a full-blown M-badge BMW. Consequently it offers a happy blend of 1-series practicality, comfort and affordability, combined with high-octane performance.

Tech spec:
BMW M135i 5 door manual
Price: £31,855
Engine: 3.0-litre 6cyl turbo
Power: 322bhp
0-62mph/top speed: 5.1s/155mph
Economy/CO2: 35.3mpg/188g/km