How to stop my fence from slipping down the slope behind my garden?

It's difficult to picture what is the problem, a photo would help. Obviously you need to stabilise the land behind the fence, but who owns the land behind the fence?

 

Hi Tom... Well as John say some photos would help.... Sounds like this could mean a few of you getting together & speaking to the developers, that might bring something.. Otherwise contact your council & get some legal advice I think Tom... They should not have dug that out without putting a retaining wall, or support for the higher ground of some kind in, in the first place, I would have thought...... Check with your council that they were not supposed to have done that originally before building works started.... So get some photos up too... :thumb:

 

All the advice given so far is correct. You need to check what provisions were made in the plans to cope with this situation. Planning should have insisted on some provision in the plans and Building Control should have enforced them. Even if Planning made a mistake and didn't make sure that provision was made Building control has the responsibility to see that everything is done safely during the construction work.

The first stop is to go to Planning, look at whether anything was said about support for the adjoining land and take it from there. Planning should want to be as helpful as possible - unless they made a mistake. Their reaction to your questions should be a bit of a clue unless you have a person who is born awkward.

If the land should have been supported then, in the first instance, the Council are responsible but ultimately the neighbour is likely to be responsible. It would be the neighbour's job to ask for compensation from the developer and/or the Council.

Of course, the Council could say that there was no need to shore up the ground and then you would need to get an independent expert to assess the situation. Don't give up because, from what I can make out from what you have said, the ground is crumbling away when it would not have done so if they hadn't dug it out.

The fence posts and fence are not really the problem. It sounds as though the rear of your garden is starting to end up in next door's garden. Is it likely to stop?

Once you have done your initial investigation with the Council you may want to get in touch with your insurance company.

Good luck.

 

It's going to be the Building Control plans that you need to see as Has Bean says. It's worth having a look on-line at the planning permission plans in case they do show retaining walls.