Jubilee or NAA.
At least, that's what I think it was. Given that it was back in the sixties, and I was nine or so, it's hard to be sure.
My uncle had let me drive his truck (with him present) and then one day put me on the tractor, made sure I knew how to work the clutch, shifter and steering and told me to take the loaded bale wagon back to the barn - don't put it in the barn, just stop and shut it off at the base of the ramp.
Boy, was I careful!!!