Look at tonight's [3 Aug] BA782. Scheduled departure 17:00, estimated departure 18:27, and my app says "We're very sorry this flight has been delayed because of a late arriving aircraft".

OK, so where is this inbound aircraft? It is BA547, arriving from Fiumicino. It indeed landed 42 minutes late. Problem, its scheduled arrival time was 16:55, so it cannot have been the aircraft that was originally intended to fly as BA782.

It could well be that the original aircraft was even more delayed, in which case the reason would be correct. But I cannot help wondering whether BA in fact covers its poor planning or lack of serviceable aircraft by the "late inbound" excuse (which in turn can be blamed on external factors such as weather or ATC, and is more acceptable by passengers)...