he won't resign if he loses the referendum, he might if it was Tory party policy to remain but it's a free vote. The party will allow him to stay until he decides to go.
if this is a quiz then I'd say Cameron. Boris has pledged he won't enter a leadership battle if Brexit wins. Why would Cameron even have agreed to the referendum if he thought it would lose him the top job? Are all the other MPs who are on the losing side expected to step down? Will Corbyn step down too?
No they won't.
Sorry, we can't find any related questions. Try using the search bar at the top of the page to search for some keywords, or choose a topic and submit your own question.