But who on earth leaked it? It (the memo briefing Ed Miliband on how to behave at Prime Minister's Questions) must have come from his own side, surely? Did they know how damaging it might be? To splash your general's secret tactics on the morning of the battle – was it as bad as they hoped?
How do you get to your feet when the world knows you've been told, "It is important to get to your feet looking as if you are seizing on something new." We can only admire the pluck it must have taken to stand up at all.
The memo warned against trying to develop a line of argument because of the atmosphere in the House. This is good advice for Ed – his best friends wouldn't claim he has the voice to cut through the turbulence. But in following the advice, he plays to his weakness. His short questions, now that we know he's following advice, make him look inconsiderable. Cameron replies at length, straying from the terms of the question, introducing his own artillery – in short, taking command of the field.
Ed asks a tightly framed question about reducing housing benefit by 10 per cent – Cameron replies with a crowd-pleasing trope about beneficiaries getting £50,000 allowances for houses that hardworking taxpayers can't dream of. It's evasive, it isn't particularly honest, and certainly is no answer to the question, but it wins because that's the way it works.
Michael Howard – incomparably more powerful than Ed Miliband – put everything into "forensic questioning". It didn't work. It doesn't work. It's like a chimpanzee's tea party in there, there's no point bringing out the good silver for it.
"The chamber and media will be looking to your body language," he was told. You remember that Ed's claim is to "speak human" (albeit, we discover, as a second language) – but acting human is not part of his parliamentary skills suite. The fin he used to point at the Government has turned into a flipper, and he makes repetitive up-and-down motions with it that would – for a man in a pub – get his lights punched out.
Who's good at the recommended "mocking humour"? It is Cameron's special subject, so any good retort from Ed will carry bonus points. But having been bested by Cameron's "bottom" joke last week, he turned his comic ambitions on the Lib Dems unhappiness at the housing benefit reforms – at Simon Hughes "glum" and a "glummer" Nick Clegg. There was a Dumb and Dumber reference in there struggling to get out but it never made it to the open air. He jabbed Clegg with a reference to recent revelations: "No wonder he's back on the fags!" (Laughter.)
Even that piece of humour went awry. Bob Russell stood to lefty cheers from Labour – but he chastised the leader of the opposition for "the fun and games" over housing benefit. True. "Mocking humour" cuts both ways. If Ed is red, it's a sign he's bleeding.