Very few who've sampled the 641bhp, twin-turbo fury of the McLaren 650S have emerged from under the car's butterfly doors and said: 'Yeah, but it could do with a chunk more power, right?'

Which makes the mind boggle all the more at the news McLaren will unveil an yet faster version of its 'mainstream' supercar at the Geneva motor show in March.

Let's talk about the dazzle-camo first – the lurid monochrome swirls are in fact a print of countless McLaren F1 LMs – the famous 'longtail' version developed as a slipperier model to succeed on the long straight of Le Mans.

Word is the upgraded 650S will take inspiration from that very car, and have the initials 'LT' (for long-tail, keep up) bestowed upon it. Black cloaking around the rear of this test mule hints at a protruding posterior.

Spotted that extra air intake on the car's flank? If extra cooling is required, you'd imagine there's a dollop more power on board – 675PS is being mooted, or 666bhp in old money. The devilish connotations of that output will surely not have been lost on the engineers in Woking.

The '675 LT' may also be the first McLaren to receive the 'lightweight special treatment', as per Porsche's GT3 RS and Lamborghini's Superleggera efforts. The 650S provides a good base, with its carbon tub helping towards a svelter kerbweight than the rivaling Ferrari 458 and Lamborghini Huracan. Some P1-pinched diet tips could be shared with the LT, potentially making the 597bhp Ferrari 458 Speciale's power-to-weight ratio look, dare we say it, a little bit limp.

It's not as if Ron and co. aren't busy enough as it is. Don't forget, McLaren's also working on its new Sports Series models – the entry-level, £120k 911 Turbo chaser due later this year. Oh, and Geneva will see the full reveal of the P1 GTR. Yup – more Le Mans-related initials. When McLaren applies them to a car, it tends not to pull half-measures.

Roll on the Geneva show...