What Gordon said to David

When Tony Blair and David Cameron walked through Parliament together last year to listen to the Queen's Speech, apparently they were having an animated chat about what the Prime Minister thought of the actor who played him in the film The Queen.
This year there wasn't the same repartee between the party leaders, as the new Prime Minister used the three minute stroll to deliver a monologue and the leader of the Opposition managed no more than the occasional "yes... yes".
Adam Boulton, Sky News's veteran political commentator, was for once at a loss to guess what was said. "I never noticed before that David Cameron is three inches taller than Gordon Brown," was all he could manage.