Any person may arrest without warrant anyone who is, or whom he, with reasonable cause, suspects to be, in the act of committing an arrestable offence.
Where an arrestable offence has been committed, any person may arrest without warrant anyone who is, or whom he, with reasonable cause, suspects to be, guilty of the offence.
Where a constable, with reasonable cause, suspects that an arrestable offence has been committed, he may arrest without warrant anyone whom he, with reasonable cause, suspects to be guilty of the offence.
A constable may arrest without warrant any person who is, or whom he, with reasonable cause, suspects to be, about to commit an arrestable offence.
For the purpose of arresting a person under any power conferred by this section a constable may enter (if need be, by force) and search any place where that person is or where the constable, with reasonable cause, suspects him to be.
This section shall not . . . prejudice any power of arrest conferred by law apart from this section.