There is no one reason for this fiasco....
BA obviously didn't train and let the staff become fully familiar with the terminal etc etc.
The BAA are a lot to blame as well. Lifts not working etc etc. Staff Car park fiasco has been going on weeks with hundreds of other terminal staff having to move to different car parks, which meant new car park barrier passes etc that didn't work...As to security check points for staff to get to work once they did manage to get to the terminal, well BAA excel l at being inept in this area. Passengers have suffered for years with security lines, and so have staff. We have to go through the same security checks as PAX every day (several times a day) so you would think that the BAA would have sufficient access points for staff....no chance. It regularly takes 40 minutes to get through the queue. Until the BAA actually decide to ruj an airport not shopping center there is no hope..