I sort of agree and disagree with Tobias-UK .

In my experience (usually weekly pre-covid now monthly or a touch less) T3 has improved a lot, but folk have long memories of the bad days. As they were truly very bad!

Staff were unpleasant and aggressive. I regularly got bag pulled for secondary for reasons such as "it didn't scan properly" (but having to wait 40mins to be told this unpleasantly as thought it was my fault). Some weeks phone in a jacket pocket (in tray) was fine, others it had to be separate in the tray. Some weeks it actually needed its very own tray! Same with laptop - ok alongside my jacket or belt one week, next week a separate tray - completely random. I was expected to know which week we were on otherwise I was shouted at!

I was bawled at for taking a sealed pack of baby food through, despite being perfectly within their own rules and holding my 12 month old son at the time. I pointed this out and it apparently needed to get escalated to a supervisor but no one was available so I asked them to chuck it as we were going to miss our flight (having stood for >90mins at bag drop and >30mins in fast track queue - which was all apparently my fault for not getting there earlier so I received another dressing down).

I could go on and always used to feel a sense of calm when I walked into the BA lounge upstairs, even though it was nowt flash, at least I wasn't being shouted at.

More recently, I've found the staff much more pleasant. Less shouty, more consistent and it's no where near as bad as it used to be. I'd say it's OK now, not great but a shadow of its former infamous-self!