I am not sure of the law now but back in 64 a 14 year old could drive a tractor on public roads.
The intent was that young farm workers could access fields around the farm where the crossing public roads was a necessity.
Of course we used to push the boundaries in those days, I can clearly remember driving a massey ferguson from Castleside to Hexam on a Sunday, three up with one driving and two standing on the drawbar hanging onto the mudguards. Oh and the tractors did not have roll cages in those days.
Free wheeling down the A68, wind in my hair (I did have some in those days) was probably where my passion for speed all started!