Fools can rush in, as the song put it, but not MLAs. Well dare they, Speaker William Hay insisted yesterday.
Assembly members could not question a Minister on a statement if they have not been actually present in the Chamber to hear it, he told the politicians using his very best headmaster's voice.
And he would not accept the excuse that they had been listening in their rooms just before bustling along the corridors.
Will Hay, of course, was a famous comic whose quintessential headmaster in films like The Ghost of St Michaels brightened up the British big screen of the 1930s.
William Hay, on the other hand is not just as famous for comedy but lightens up the Big House nowadays.
It was a day for the comedic. Even the Deputy First Minister, one half of that newcomer duo the Chuckle Brothers Ian and Martin, who are about to go on tour of some big venues in England, had a go at doing Frank Carson.
Danny Kennedy, chairman of the Chuckle monitoring committee, had attempted to entrap the senior republican over national sovereignty and local honours to replace the Queen's.
"That's a cracker," McGuinness replied.