This section applies in relation to any land if the relevant local planning authority has reasonable grounds for suspecting that an offence under section 160 or 161 is being, or has been, committed on or in respect of the land.
A person authorised in writing by the relevant local planning authority may at any reasonable hour enter the land for the purpose of ascertaining whether an offence under section 160 or 161 is being, or has been, committed on the land.
A person may enter a building used as a dwelling-house under subsection (2) only if 24 hours' notice of the intended entry has been given to the occupier of the building.