The England training session at St Paul's School the week before the opening game of the Five Nations Championship against Wales, was the first England training session I recall attending (editing my archive may prove me mistaken).
I was surprised that half way through Roger Quittenton was produced as if a rabbit out of a hat and the press was witness to what seemed to be (and was described to us as) an impromptu game between the England side and a selection of other players brought in specifically for the task. Clearly as Roger was there there was nothing impromptu about the proceedings :-)