The inevitable expansion of the 1-series range is upon us, spearheaded by the mighty new 135i – a 302bhp, 155mph coupe.

Three versions of the 1-series coupe will be offered in the UK – an entry-level 120d, a mid-range twin-turbo 123d and the M-in-all-but-name six-cylinder 135i. All three will go on sale in the UK in November. Prices are yet to be set, but are expected to range from around £21,000 to just under £30,000.

The new coupe bodyshell features a cosy 2+2 cabin and an elegant, coupe silhouette that’s 133mm longer than the slightly awkward-looking hatchback and 1mm wider. Underneath, the rear-drive chassis uses the same largely aluminium suspension as the hatch, tuned for a slightly sportier ride.

The range-topping 135i takes its 3-litre twin-turbo straight-six from the 335i. BMW claims a peak power figure of 302bhp at 5800rpm and 295lb ft from as low as 1300rpm, enough shove for a Cayman-beating 0-62mph time of just 5.3 seconds. The 135i will also sport a version of DSC that acts like a limited-slip differential, and an M aerodynamic kit as standard.

The 123d has all-new 2-litre twin-turbo in-line four. All-aluminium in construction and boasting a specific output of over 100bhp per litre, the engine develops 201bhp and 295lb ft.