You don't believe me? That's an extremely weird reaction, he's on public record with this kind of behaviour, just look at most of the comments in this very thread of people saying the same thing.

You've forced me to look up the talk, and the one I have the ticket for in my email is actually from 2011, my memory of the date was wrong: https://localevents.theiet.org/register.php?event=bc7fd2

Someone took a terrible video of it (ah 2011 video) here https://www.youtube.com/watch?v=vazlMe7sNzM but that doesn't seem to include the Q&A section where he went off the rails.