One of the wonderful virtues of the parliamentary system is that the Constitution is what happens. Our Constitution is a little bit written; the British Constitution is a whole series of cases and events with many conflicting things.
I tried to give examples of prorogations that were very short and happened after a session that only lasted a few days and prorogations that were very long and happened after long sessions. Every one of those was justifiable.
I had a feeling that motion covered too little and didn't really cover it in a way I was comfortable with. You wanted to get at the Prime Minister advising prorogation in order to escape the scrutiny of Parliament. Every time I go back to it I say that if it is going to be entrenched in Standing Orders or legislation, it has to be that prorogation be supported by a motion in the House of Commons.