I'd like to show a film as part of a film club or a student society activity. Do I need a licence?

Showing films at a film club event requires a licence, unless the specific film is out of copyright (which is unlikely to be the case). Film screening for non-teaching activities is not covered by copyright exceptions, which only apply to educational activities.

You may want to check with copyright@ucl.ac.uk whether yiur film is covered under our current subscriptions, including Kanopy.
You may be able to get a licence for a one-off screening from Filmbank or the MPLC. If the film you choose is not in their repertoire, you may need to track down the rights owners. The cost of the licence will need to be covered by the department or student society.