You cannot let in Northern Ireland until Tourism NI has certified the property

Certification is a condition of opening, not a badge

Two smaller offences travel with the main one. You may not advertise or describe your property as certified tourist accommodation when it is not, and you may not let someone else do so on your behalf. And once you hold a certificate, it has to be displayed in the premises at or near the entrance, or wherever Tourism NI specifies. Owners of remote cottages file the certificate with the deeds; it belongs on the wall inside the door.

Eight categories, and the one that catches people out

Tourism NI certifies eight recognised categories: hotel, guest house, bed and breakfast, guest accommodation, self-catering (which expressly includes the sub-letting of caravans and mobile homes), hostel, bunk house and campus accommodation. Most owners we speak to fall into self-catering or guest accommodation, and the category you apply under matters: if the property does not meet the minimum criteria published for that category, the application is refused rather than downgraded.