I’ve been flying out of LCY every Friday for the past 6 months and they changed the security arrangements ~3 weeks ago. At the time I check-in they now have 2 conveyor belts operating but only metal detector (used to be 2). This soon causes a queue of people waiting and then then the trays back-up on the conveyor belts because the passengers aren’t getting through to unload them and it grinds to a halt.
Last Friday was the worst so far and I was in the security queue for ~25 mins (so much for the 15 min check-in time) and it was pretty tight for my flight. As a result of that, I’ve changed to LHR this Friday (and to visit the F lounge again ) so that is 1 passenger less in the queue.