My parents have a bungalow without a chimney but they needing to build one to support a log burner. Do they need planning?
Not only may they need planning permission but they may also require building regulation approval, depending on the extent and location of the chimney. You may find it useful to also visit your local authority website as each LA publish their own planning and building regulation requirements in detail.
From experience, if you prefer to telephone them they can also give you this info over the phone for free.