If you are going through T3 security, absolutely make sure that you remove every bit of liquid, even tiny tubes, from your bag. Look through your bag and find every bit of it and put it in a clear plastic bag thing. It's very easy for things to be buried there, especially for us frequent flyers who may not pack/unpack the bags any more and leave it permanently packed. It's so easy to forget something you dropped into there.

Forgetting to do so will potentially incur a BIG delay and it might even make you miss your flight (or miss out on the lounge champagne... which I went to check for the benefit of the esteemed members of this forum and can confirm that mini bottles of Laurent Perrier and full size bottles of Balfour rose in the T3 F lounge but I digress).

I have just been held in a queue for a secondary search of the bag for 25 minutes at fast track because I forgot about a tiny (not even 50 ml in total) amount of liquid in my bag. Completely my fault to have forgotten about that, but the process was nevertheless very inefficient.

If you have left some liquid in your bag you'll hear a beep and your bag will be held aside. There isn't enough staff to go through the bags to literally remove everything from the bag one by one, swab most things and re-scan the bag and the liquid, so there are lots of people waiting for the secondary search.

They are not just getting you to take the liquid out of your bag and rescanning the bag. They are taking everything out of your bag themselves.

If you do forget to remove every bit of the liquid, you are risking missing your flight as you may well be held in the secondary bag screening queue for 30 minutes or so.

Lots of very, very grumpy passengers, and lots of pressing of the red buttons on the "How was your Fast Track experience" machine! Staff members are asking passengers to complete complaint forms because they don't seem happy with the delays either.

So, excuse my shouting, but REMOVE EVERY BIT OF LIQUID FROM YOUR BAG, PUT IT IN A 1-LITRE PLASTIC BAG (no other bag seems to do) AND PUT IT IN THE TRAY. Do not leave it in your bag.

As long as you have absolutely no liquid in your bag, you will be able to get through security pretty quickly as they are not holding up the whole queue while they do a secondary screening. At least they are putting the bags aside for that and letting others go through.

P.S. T5 may be doing the same, but I don't know, as I haven't been through there for about 10 days or so.