I was on Thursday's BA2647 MLA-LHR. We ended up departing around one hour late due to the late arrival of the plane. Once on board, the captain informed us this was because the plane was late leaving Heathrow since they identified a bag had been loaded which shouldn't have been onboard, and because of the security threat this had to be resolved. Interestingly the 'sorry you were delayed' email described this as "operational constraints".

Naturally I'm glad they took the time to resolve the issue and am not at all fussed about the delay (the further delay on arrival at LHR waiting for a stand and bridge is another matter!). However it got me thinking - how does a bag get incorrectly loaded and is this a regular occurrence? More intriguing is how does one know there's a bag on board which shouldn't be? Is every item of luggage scanned again when being put into the actual aircraft, and if so why would it continue to make its way into the hold? Or was the actual problem somewhat different and this was the most simple description for the average passenger to understand?

If anyone has any insight I'd love to know to settle my curiosity! On a side note the flight itself was brilliant with a superb crew at the front, and my first time trying the Shepards pie!