"The fact is no-one really know how they would behave in extremis. And that applies to pushing the button as well. It matters not a jot whether Cameron or Corbyn think they would or wouldn't when it comes to the crunch. Where is does make a difference is beforehand, in things like deciding to renew Trident or not."

Agreed. Depending on which way you want to look at it, Corbyn was either naive in the way he answered the mischief question or he was showing a refreshing dose of political honesty.