I think we know what's happening here. A camp within the Labour manifesto-drafting team always wanted to include the WASPI pension giveaway. McDonnell overruled it as being too costly. The compromise was to keep it up their sleeves in case the other unicorn-promises weren't doing the trick.
Come Saturday's daily war committee, there's panic in all eyes: it ain't working! Tories pulling ahead in the polls. OK, says McDonnell, f**k it, we'll unleash the Big One. So WASPI it is.
But given the disbelief with which the rest of the giveaways have been greeted, is doubling down going to work the trick? Hard to tell. WASPI gets some very heated middle-aged ladies very heated indeed. I'm almost surprised every party didn't offer something on this, much like they all promised 'something' for Equitable Life victims (such as, errr, myself).
It all reminds me of an episode in Blair's 1997 successful campaign. Curiously and needlessly, halfway through he got nervous: even John Major seemed to be doing OK. Whadawe do now, Alastair? Campbell handed him the doomsday script: Blair put on his ashen face for the cameras, drew himself up to his full height, gripped the lecturn with whitening knuckles, paused at length for maximum effect, set his lower lip a-trembling, and pronounced the Big Lie: "The Tories ... are going to scrap the state pension!"
We may see a replay of one like that in the next couple of weeks, if the polls don't look any better for Corbs. Campbell will be preparing a choice of scripts even as I write.
UPDATE: I have just found this - a bullet-list of the entire Labour manifesto. There (appox) 570 pledges. Overcooked? Looks like it.