The exchange happened. It's just that the historian is using a third party 'quotation' of what was said and people remember there being something like that.
The actual exchange wasn't as vicious from a language perspective, but it's the look in May's eyes when she delivers it:
The Mandela Effect is people remembering things that never happened rather than misquoting things that did. The historian didn't remember hearing the quote he searched for and the quote he searched for turned up no results because of this. Other people remembered there being an exchange but the actual quote was different.
It's at about the seven and a half minute mark in the following (assuming this is the one everyone thinks they remember):
No, the Mandela effect is people remembering things differently to what actually happened - I.e a false memory - that can either be something happening completely differently or just being a change to what actually got said or what something was called.
There are countless examples of that happening, and in each case the thing happened, just differently - Mandela was in jail but didn't die, Kirk said many ways to get beamed up but never said beam me up, Scotty, many people say Snow White says mirror mirror on the wall but she says magic mirror etc
Ziggys exact quote was
"
I distinctly remember this because that answer, together with the look on her face, was very menacing and filled with hatred. Not seen that before or since. So I thought I would look it up and check the YouTube of the exchange. It’s not there…but the most sinister thing is it doesn’t appear in Hansard
according to an historian who went looking too,
although a lot of other people seem to remember the exact words said."
That's multiple people remembering something that she didn't say. Yes, the exchange happened between May and corbyn, but look at that quote above; especially this bit;
"with the look on her face, was very menacing and filled with hatred. Not seen that before or since."
Ziggy, like the others, is sure she said that but also sure about this look of menacing hatred. You've just posted the video and sure enough at 7 & a half minutes in, she says something different (but similar, same with all the other Mandela examples), but not only that I don't think she has menace or hatred in her face, it's just standard PMQ stuff, and despite being a full old hag of a witch, she is even holding back a smile as she said it
It's completely different to how it has been remembered, unless you're the most die hard labour supporter I suppose. It's certainly an interpretation, anyway and you could say the same about most PMQ. But either way, multiple people have remembered this being said differently
www.healthline.com
