I know this is old news, but since I only managed to add this time today, I figured it might still be worth putting together few sentences, expressing my thoughts on this spectacular laptime.
First of all, congratulations to McLaren for beating Huayra, despite the great lenghts Pagani were going to in order to beat Bugatti Veyron Supersport and the rest of the "recognised" Top Gear laptime holders.
Remember those "extra special" tyres on Huayra? I do not know if McLaren pulled similar stunt themselves, but I do know that Dunsfold airfield is, or at least was, McLaren's own proving ground since development of MP4-12C, which the McLaren 675 LT is somewhat remotely based on. So it was no surprise that 675 recorded a fast time. Surprise was that it beat Huayra, even if by a tenth of a second.
It was also pleasure to watch the 675 lap. The car was on tyre grip limit almost the entire time - both in terms of handling grip and traction on acceleration. It seemed obvious to me that driver had some kind of traction control enabled, because the car didn't loose traction for one second, even on slow corner exits and on uneven surface.
It is just a shame that there is this "petty" Ultima GTR with a laptime almost a second faster, and the "dis-owned" Caparo T1, which, by the way, is road legal in some countries, and even faster than Ultima.
It remains to be seen if LT's bigger brother McLaren P1 can challenge the Caparo record. My intuition says it probably can't - difference between LT and P1 in terms of track capability is probably less than most people think.