Pressing

We have aircraft carriers with no aircraft, so why not nuclear submarines with no nukes?

Jeremy Corbyn is one of only two Leaders of either party whose views on the monarchy have ever been asked. The other was William Hague, in the run-up to the 2001 General Election.

"Do you believe in the monarchy in principle?", Hague was asked on the Today programme, so that the response to his "Yes" could be, "So, only for the duration of the next Parliament, then."

The interviewer, I think that it was John Humphrys, went on, "And the British nuclear deterrent, is that only for the duration of the next Parliament, too?" He received no answer.

Whereas we also know that Corbyn would not launch a nuclear strike.

On Wednesday, he needs to be the first person ever to pose that question to David Cameron, who has never been asked it.

Thereafter, it also needs to be asked of George Osborne, Theresa May, Boris Johnson, and anyone else who might fancy succeeding Cameron in this Parliament.

As well as of each and every one of Corbyn's critics within his own party: "Would you ever launch a nuclear strike?"

"Under what circumstances?" would be a follow-up question. This, a Yes-No, needs to be the starter for 10. Number 10.