I'm trying to construct a post and wire fence for my summer raspberries. I've got 8ft posts buried 2 or 3 feet in the clay soil but the blighters keep falling inwards and the wire seems to slacken as soon as my back is turned.
I've tried concreting them in but even this won't hold them. I've noticed a skip next to the allotment is full of rubble. If I filled the post holes with rubble and put a bracing post in do you think this might work?

Any advice?