As the fence does not belong to you legally you have no right to attach anything to it, nor would you have had the right to attach anything to the wall. I suggest before you do anything you sound your neighbours out as to how they would feel about you using their fence to train fruit trees on. Unless the fence is substantial the weight of the trees could damage it and, you certainly won't be able to paint.

I would set up tentioned metal angle iron or treated heavy wooden posts about 12 inches in front of the fence and train your fruit trees and climbers on metal wires. That way you will not have to interfere with the neighbour's fence and create a good air flow all around your plants. Your neighbours can then paint or remove any part of their fence without damaging your plants.

Makes good sense Jimmy

Yes agree with jimmy that's the way forward, before you paint the fence though it would be best to speak to your neighbours to see what colour they have painted theirs, let's just say they have painted it in one of those barmy bright colours and you paint with dark oak and it runs through onto theirs, then trouble could start so best to be safe.

The rules regarding boundary fences are not rigid. On our deeds it states that any boundary structures are owned jointly, no matter who has paid for it. We only discovered this when our neighbour told us we had no right to even touch the fence he had erected. We then consulted a solicitor and asked her to interpret the deeds. Needless to sya the neighbour was furious but his lawyer agreed with ours. Just a point of interest.

Where we used to live the rule was that the fence belonged to the person on whose side the supports were. (This was before the fences with concrete bases where the fence slots in half way across...)

Still is up here Stera where they don't use the concrete bases so it is down to the fence owner to do any painting.

Wonder what happens when the fence owner wants to put preservative or paint on the other side... we've never lived in a house with wooden fence long enough for the situation to arise.

Mostly these things are dealt with amicably in my experience... We have a hedge on one side and a fence on the other, this is ours erected to replace a privet hedge which took up two metres of the garden; it was creosoted all those years ago when erected and hasn't been touched since as we prefer a natural look. Neighbour doesn't give a hoot as it can't been seen for clambering clematis, winter flowering jasmine etc.