Are you in or out?

I don't know if I've got a particularly "outside the box" sort of mind, but so many times it seems to me that a crucial question is not answered - or even asked.  Do you remember the case of the journalist who was detained at Heathrow as he was passing through and his belongings confiscated (see post dated 20/8/13)? The Court of Appeal have held that this was legal under the provisions of the infamous Schedule 7 of the Terrorism Act 2000.  I've no real problem with that - whatever I think, that's their ruling and that's what they're there for, but what about the fact that he was in transit?  This wasn't mentioned at all, but my understanding is that if you are in transit you haven't entered the country (remember the film "The Terminal" which was based on true events?) in which case the question is - did the Terrorism Act (or any other UK legislation for that matter) even apply?  Answers on a postcard...