Due to someone's carelessness with a photocopier - and how easy it is to leave that last sheet under the flap if you're rushed - Tory MPs were all holding the same document as Francis Maude, the Conservative MP for Horsham and the shadow Chancellor, got up to speak. The hasty scrawl across the right hand corner probably best conveys both what it was and what it meant to them. "Labour's proposed interventions on Francis", it read, "Recovered from a photocopier. Tee Hee!!" "Tee Hee!!" indeed. Not to mention "Chortle!" and "Guffaw!!!".
There is a convention during oral questions to ministers that MPs do not take up the House's time by laboriously repeating what is already written on the order paper. They simply get up and announce the number of their inquiry. "Question Number Six, Madam Speaker," says Jeremy Corbyn, the Labour MP for Islington North, and the minister responsible sets off into the arid terrain of a prepared reply about the future of the Western Sahara.
Yesterday Opposition MPs, to their uncontained glee, were able to reverse this procedure.
So, up gets the unsuspecting Geraint Davies, the Labour MP for Croydon Central, to ask Mr Maude to give way. He is all eagerness. "Will the shadow Chancellor say whether he is in favour of Bank of England independence or against it? Yes or No?"
"Number Ten!" bellow the Tory backbenchers in unison, giving notice that the crib sheet is in general circulation. Inexperienced Labour goodie- goodies found themselves in a quandary. Francis Maude is a temptingly easy target for ambitious backbench submarine commanders, wallowing heavily as he proceeds and armed only with light and inaccurate weaponry. How alluring he must have looked through the cross-hairs of their periscopes. But the sea-lanes had been mined with depth charges and already one of their comrades had gone down, leaving only a greasy swell behind him.
Set course in the wrong direction and "Boom!" the Opposition would explode again in mocking laughter.
Only Dale Campbell-Savours, the Labour MP for Workington,had worked out a tactic to get round the problem - by deliberate detonation. "Perhaps I can further develop Number Eight on the list," he began affably, and when the enormous splash of Tory hilarity had finally subsided, he released his torpedo: "He can't say he doesn't know the answer, because he's been given notice."
Not all MPs need their questions typed out for them. Earlier, MPs on both sides tried to press Robin Cook, the Foreign Secretary, to declare that it was now policy to terminate President Saddam Hussein's political career with extreme prejudice. "Can't we be more robust," said one MP plaintively, clearly longing for the moment when the boys from Hereford would be asked to "aid the opposition".
Mr Cook simply reiterated government determination to make Iraq comply with UN resolutions - at which point he was hit from behind by a low-flying dove. "What would be the point of bombing Baghdad, a city of four-and a-half-million people which has only two ambulances?" asked Tam Dalyell, the Labour MP for Linlithgow, gloomily, "Another Dresden?"
Judging from the asperity of Mr Cook's reply this intervention had not passed through the Millbank opinion mill.