A constable or enforcement officer may enter premises if he reasonably suspects that an offence under this Act may be—
being committed on the premises, or
about to be committed on the premises.
A justice of the peace may on the application of a constable or enforcement officer issue a warrant authorising a constable or enforcement officer to enter premises if the justice of the peace is satisfied—
that there are reasonable grounds for suspecting that an offence under this Act has been committed on the premises,
that there are reasonable grounds for suspecting that evidence of the commission of the offence may be found on the premises, and
that at least one of the conditions in subsection (3) is satisfied.
Those conditions are—
that admission to the premises has been refused,
that admission to the premises is likely to be refused unless a warrant is produced,
that the purpose of entry may be frustrated or seriously prejudiced unless a constable or enforcement officer arriving at the premises can secure immediate entry, and
that there is likely to be nobody at the premises capable of granting admission.
A warrant may be granted in reliance on subsection (3)(a) or (b) only if the justice of the peace is satisfied—
that notice has been given to a person occupying the premises, or having responsibility for their management, of intent to apply for a warrant, or
that the purpose of entry may be frustrated or seriously prejudiced by the giving of notice under paragraph (a).
A warrant under subsection (2) shall cease to have effect at the end of the period of 28 days beginning with the day of issue.
In the application of this section to Scotland, any reference to a justice of the peace is to be construed as a reference to the sheriff or a justice of the peace.