This got a little discussion yesterday on the BAEC board:
MAN airport security disaster
When I see slowdowns in security at airports like LCY it's when folks unpack their x-ray trays very slowly, without taking them away from the conveyor. This causes the queue to back up, because the trays are unpacked much slower than they're scanned.
At MAN last night I saw a second, even worse dysfunction: Because so many trays were diverted to secondary screening, the X-Ray machine was backed up, and every single passenger felt it: Not just the folks waiting to be told off for their water bottle or ipad, but everyone: because no trays could get through until more bags were inspected.
I was in the FT queue and thankfully got through in under 30 minutes. 20+ of which was spent standing in exactly the same spot just like everyone else, waiting for bags to receive the rubber gloved tut tut.