Seriously, that's stupid that he was allowed in a car faster than an F1 car and those drivers need a special licence!
they don't need a special license at all. In fact there have been race drivers (at least in F3 and I think Nascar, not AFAIK in F1) who didn't have a driver's license.
All you need is an endorsement from a team (else you won't have a car) and a FIA race license (which is mostly about knowing the rules).
And driving a car like the one Hammond was in is easier than an F1 car. Not much need for steering, braking, etc.
It's flat out straight ahead until you hit a predetermined point at which time you hit the brakes to get it to stop before the end of the track. No corners, no other traffic, no pitstops or traffic rules.
Of course it takes some training to keep it straight, and he without doubt had that.
But suffering catastrophic mechanical problems can't be fully trained for, and at 300mph+ even a tiny unballance can be catastrophic.
Anyway, he was driving on private property. On private property the only one who says what goes and what doesn't is the owner.
I'll oppose ANY plan by the government to tell me what I can do in my own home (or my own garden, racetrack, or as in this case airfield), as that's the establishment of a total police state.