If—
making a prohibition order under this section in respect of the hazard is a course of action available to the authority in relation to the hazard for the purposes of section 5 (category 1 hazards: general duty to take enforcement action).
A prohibition order under this section is an order imposing such prohibition or prohibitions on the use of any premises as is or are specified in the order in accordance with subsections (3) and (4) and section 22.
The notice may not, by virtue of subsection (3)(b) or (c), prohibit use of any part of the building or its external common parts that is not included in any residential premises on which the hazard exists, unless the authority are satisfied—
A prohibition order under this section may relate to more than one category 1 hazard on the same premises or in the same building containing one or more flats.
The operation of a prohibition order under this section may be suspended in accordance with section 23.