RSA 544:41: Avoidance of Leases.

If a tenant or occupant of a building or tenement, under a lawful title, uses such premises or any part thereof for any of the unlawful purposes enumerated herein such use shall annul and make void the lease or other title under which he holds and, without any act of the owner, shall cause the right of possession to revert to him, and he may, without process of law, make immediate entry upon the premises.