Not sure if this is a new thing or not can't find any other posts on the forum.

Coming out of the lifts from the tube into T5 departures there are BA and Airportr staff. If you are checked in and have a boarding card you can drop your bags there free of charge and head straight to security. They said it was because it was busy but the bag drops didn't look too bad this morning. Might be of some benefit when it is busier.