A constable may, at any time during the period of a designated sporting event at any designated sports ground, enter any part of the ground for the purpose of enforcing the provisions of this Act.

A constable may search a person he has reasonable grounds to suspect is committing or has committed an offence under this Act F1....

A constable may stop a public service vehicle (within the meaning of section 1 of this Act) F2or a motor vehicle to which section 1A of this Act applies and may search such a vehicle or a railway passenger vehicle if he has reasonable grounds to suspect that an offence under that section is being or has been committed in respect of the vehicle.