When I got my PPL, the old brown, CAA, ICAO compliant one, I recall my examiner asking if I understood what that allowed me to do. She went on to say that if I had enough money or found someone foolish enough to let me, I could even fly a light, single engine jet, and that to me with a long standing liking for the Folland Gnat. It wouldn't be sensible, she said, but it would be quite legal.