If the leader dies, resigns or loses their seat in Parliament, the deputy leader (if there is one) serves as interim leader until a leadership election takes place. This has occurred three times, with Menzies Campbell serving as interim leader following the resignation of Charles Kennedy (Campbell was elected leader in the ensuing election) and Vince Cable serving as interim leader following Campbell's resignation.
If the party leader passes away, steps down, or loses their parliamentary position, the deputy leader (if present) assumes a temporary leadership role until a new leadership election is held. This has happened on three occasions, with Menzies Campbell taking over as interim leader after Charles Kennedy's resignation and subsequent election, and Vince Cable serving in the same capacity following Campbell's departure.