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 ceases to function, steps down, or loses their parliamentary post, the deputy assumes a temporary leadership position until a new leadership election is held. This has occurred on three occasions, with Menzies Campbell succeeding Charles Kennedy after his resignation and subsequent election, and Vince Cable serving as interim leader following Campbell's departure.