At the time I was settling back on cruise control at 60 after overtaking a vehicle ourselves. The Maserati was in my blind spot in the overtaking lane when I heard the engine give that almighty growl and it accelerated past at what looked to me like a rate of acceleration mere mortal cars could only dream of. It wasn't a discernible single speed per-se because the vehicle was accelerating hard at the time
The road was wet although there didn't appear to be any standing water pools or debris in the road. Significant spray was thrown up into my windscreen as the car went past, which given how distant the incident is from us now in time, always reminds me just how damp it was that morning.
Through the spray we saw the rear end of the Maserati stepping out to the right of the vehicle, it span broadside in the road, moving into my lane although it was a few car lengths ahead by this point with that powerful acceleration. The spin continued bringing the vehicle back around facing towards the opposite side of the road now which it traveled towards. It must have span completely round a couple of times.
As it left the road onto the grass verge on the opposite side it was traveling backwards right side up, but due to the inertia it had from it's acceleration it was still traveling in the direction it had originally accelerated in sliding along the grass verge with it's rear end sort of diagonally in it for a moment like this symbol /
Something must have contacted a wheel or something and tried to stop the vehicle sliding because it still had all that inertia and when it couldn't slide sideways and backwards down the verge anymore it rolled over a couple of times before striking the tree still in a / attitude and suddenly came to rest.
At that side of the road there is a lay-by and the vehicle was half in the lay-by, half in the lane, the contents of the boot seemed to have been ejected over the span of about 10m before the vehicle when it was rolling over.