The Oxford English Dictionary defines a STILE as:
an arrangement of steps allowing people, but not animals, to climb over a fence or wall
...which, in it's simplest form, just about sums it up.
In my ignorance, I imagined that most stiles were built on the spot, either by the landowner or by a group/organisation such as BTCV, National Trust or the National Park Ranger Service. (In fact, my eldest son spent his Y10 work experience week with BTCV, constructing a kissing gate stile on a path by the Trent - and jolly hard work he said it was too). What I didn't know was that stiles can now also be bought 'off the peg' and that all constructions are meant to conform to a new British Standard (the penalty for non conformity being prosecution of the landowner by the Highways Agency).
I wonder if this one conforms!