You need a ‘non-theatrical’ film licence to show films and TV programmes in public (but not in a cinema), for example:
at one-off events
at film clubs - whether or not you sell tickets
in common areas for guests, residents and passengers
in retail and entertainment venues
The one exception is curriculum-based screenings in state schools, where you do not need your own licence.
To run a commercial cinema you need a premises licence. Apply to your local council.