I don't think wait times at security have been the cause of any significant delays for some weeks now. The main issue now is ground handling.
I flew from T3 a couple of weeks ago and was through security in about half an hour, even with the queue most of the way back to the boarding card scanners. We ended up with a 2 hour delay on our flight despite the inbound only being 30 minutes late, due to the wait for baggage being offloaded and a PRM who was still on board waiting almost 90 minutes after landing.