This is actually an interesting discussion 
I'm not mad keen on the recent trend for party leaders in the UK quitting almost instantly after a bad result (though occasionally, as with Jo Swinson, there may be little practical alternative) but it may be possible to overdo the "debate and discussion" thing too. On this at least, Corbyn maybe has it about right?
The UK Liberal Democrats constitution requires the national party leader to be an MP, so Jo Swinson ceased to be leader when she failed to be re-elected. This is quite different from the Canadian practice, where it is quite common to select a new federal leader from outside the existing parliamentary caucus.
