To expand what emcl said:
Short answer is that all traction controls are active if it is set to track/track on all Mclaren cars.
12c/650/p1 (even in race mode). The ESC is on. To take it all off; one has to push the "aero" and "manual buttons" simultaneously and hold. One will get a warning and then ask to confirm. To confirm you would then push those two buttons again simultaneously. It will be all off and in the screen it will say that ESC is off and it will be in red. My experience is that the ESC isn't so intrusive with it being on and in track/track mode.
570/675/600LT/720s - track/track the ESC is still on. However, there is another mode rather then just all off. It is the ESC dynamic mode. Just press the ESC button once and on the dash it will say es-dynamic in yellow. This is the best mode to run the car in. There is still plenty of ESC on but the car is very playful. It is the equivalent of being in Race with a Ferrari. If you ever think you have turbo lag, hit the limiter, etc. then it is probably because you are not in ESC dynamic mode. This is very important on track to drive in this mode. You won't be getting the proper driving experience if you aren't in the ESC dynamic mode. These cars will cut power on you all the time. To take it all off, you would be in ESC dynamic mode and press and hold the ESC button again and you will get a warning and it will ask you to confirm. Once you confirm then the dash will show ESC off in red.
On a race track or when used for performance purposes then it is a MUST to be in ESC dynamic mode. (note; you don't have to be in track/track mode to get into ESC dynamic mode).