Work is already underway on the development of an even faster McLaren Senna LM following an image surfaced of, what's thought to be a late-stage development mule, that was spotted completely undisguised.
The sole pic, posted on a Pistonhead's forum, is thought to have been snapped at a facility owned by McLaren or MSO, hence the presence in the pic of the McLaren F1 in the background that's likely to be 'XP5' – one of the five original prototypes.
Rumours have been rife for some time that the Senna LM is on the way following unconfirmed designs leaked online but, until now, some thought the 'LM' was nothing more than a colour scheme for a none-off car created by McLaren's MSO bespoke division.
Painted in wild Papaya Orange with 'LM' graphics lifted off the original McLaren F1 LM, the Senna's missing front fender suggests development is on-going – or an engineer has had a costly (and embarrassing) shunt.
Changes for the LM version suggest the fastest-ever road legal Senna could be based on the £1.1 million ($A2.2m) Senna GTR created for wealthy track-day fans.
Expect the LM version to shed weight, including ditching its glass roof for a lightweight composite version.
The wheels, meanwhile, mimic the F1 LM's and are thought to be developed to be among the lightest of any fitted to any production vehicle.
Inside, there's plenty of 'LM' decals and full carbon-fibre bucket seats with no added weight-saving.
Plexiglass, instead of real glass will be evidence of yet more kilo-cutting while the standard car's trick variable ride height might be axed for a fixed suspension likely to have been derived from the 720S GT3 car.
Set to feature a development of the road car's aero, the Senna LM will fall short of pinching the Senna GTR's extreme wings and spoilers in a bid to ensure it remains road legal.
The ultra-limited run on of Senna LM's will also miss out on the GTR's more powerful twin-turbocharged 4.0-litre V8 as the track-only Senna's extra 19kW (607kW and 800Nm) comes from sacrificing the secondary catalytic converter meaning, again, in some markets the faster Senna will fail to meet emission requirements.
The original McLaren F1 LM was a more track-focused version of the British hypercar that was built to pay tribute to the five F1 GTRs that won and competed in the 1995 Le Mans 24 Hours.
Back in 2016 the famous 'LM' moniker was brought back from the dead on six McLaren P1 GTRs that were converted to a road-legal specification by Lanzante Motorsport.
The P1 LMs featured huge rear wings, a large front splitter, and anti-dive planes that helped them generate up to 40 per cent more downforce than the standard P1.
Lanzante, the private race team responsible for the epic 1995 Le Mans F1 win, was commissioned by MSO on behalf of demands from its wealthy customers.
It's not known if the British motorsport and engineering firm has been recruited once again.