You will rarely need planning permission to erect a fence for a normal family home, but the general rules are as follows:
The fence is not taller than a total of 2 metres
If you are replacing an existing fence that is already over 2 metres, the new fence should be no higher
If the fence is next to a highway or footpath alongside a highway, then the fence should be no higher than 1 metre
The right to erect a fence hasn’t been removed by another direction or planning condition.