I dont know if thats fact or not Ill look it up, certainly these fences do angle in as you have suggested but Im not 100% on the reason. Its difficult to climb either way but I would go so far as to say its harder to climb the way Neil has done it, bird table principle, however if its angled away from the property then the top of the fence would be outside of the property line of what its protecting thus encroaching over someone elses boundary hence it usually angles inward. It then of course has the added bonus of trapping intruders inside but Im sure thats just a nice side effect! Neil may well be justified leaving it as the car park I assume also belongs to Deeping Lane depot. Im gonna do some digging I think. However if you are in fencing or sonething then I apologise for doubting your knowledge. As a mischeivious kid I have climbed such fences and used my coat over the top to scale the wire. I could only do it one way. With the wire going away from me.
Edit: Bit of research done. Link to page. The human resistance bit mentions wire leaning towards the intruder.
http://en.m.wikipedia.org/wiki/Barbed_wire