Most fences don't require planning permission however:
You will need to apply for planning permission if you wish to erect or indeed add to a fence, gate or wall and:-
If it is over 1metre in height and next to a highway used by vehicles or the footpath of such a highway; or over 2 metres elsewhere.
Or an article 4 direction or a planning condition applies to your property*; or
Your house is a listed building or in the curtilage of a listed building;
The fence, wall or gate or any other building forms a boundary with a neighbouring listed building or its curtilage.