4.—(1) Any person authorised by a relevant licence holder may at all reasonable times, on the production of some duly authenticated document showing his authority, enter any premises to which gas is conveyed by that licence holder for the purpose of—
(a)ensuring the safety of the gas system on those premises or of gas fittings; or
(b)carrying out any necessary works of maintenance, repair or renewal of any part of the gas system on those premises;
(c)in the case of premises where the relevant licence holder has reason to believe that a compressor or compressed air or extraneous gas is being used, inspecting the premises and ascertaining whether any safety requirements imposed by the relevant licence holder on the consumer are being complied with.
(2) In paragraph (1)—
“compressor” means an engine, gas compressor or other similar apparatus or any apparatus liable to produce in any main of the relevant licence holder a pressure less than atmospheric pressure;
“compressed air” means air at high pressure; and
“extraneous gas” means any gaseous substance not conveyed by the relevant licence holder.
(3) Any person authorised by a relevant licence holder, after 24 hours' notice to the owner of any unoccupied premises, may at all reasonable times, on production of some duly authenticated document showing his authority, enter those premises for the purpose of—
(a)disconnecting any gas fitting or any part of the gas system on the premises or cutting off the supply of gas to the premises; and
(b)removing any gas fitting or meter belonging to the licence holder.
(4) The notice required to be given by sub-paragraph (3) may, where the owner of the premises is unknown and cannot be ascertained after diligent inquiry, be given by affixing it upon a conspicuous part of the premises not less than 48 hours before the premises are entered.
(5) The powers conferred by this paragraph may only be exercised where the relevant licence holder has reasonable cause to suspect that there may be a danger to life or property in connection with the presence of gas on the premises in question.