Quoting Scoobys:
I flew as an f/a doing long haul for years, if I was given a quid every time someone tried to bin or burn their passports in the lavs on arrival into egll I'd be a millionaire, then they would tell immigration they where from a different country,have been persecuted and have just so happened to have lost their passports and please Mr Blair can I have asylum.
unquote
I was once airline staff at a major airport. The same thing happened there! Traveling on a fake passport is not necessarily related to terrorism! In an earlier post someone suggested that the supposed itinerary of the users could mask their country of origin, making a repatriation difficult. Sounds plausible too!